Abstract of the 4th International Online Conference on Crystals ^†

Abstract

The 4th International Online Conference on Crystals (IOCC 2024), Part of the International Electronic Conference on Crystals series, was held online from 18 to 20 September 2024. This is a new and improved initiative based on the experience from the first, second, and third International Electronic Conference on Crystals. The fourth conference was organized around seven topics and related themes: Liquid Crystals, Crystal Engineering, Inorganic Crystalline Materials, Organic Crystalline Materials, Hybrid and Composite Crystalline Materials, Materials for Energy Applications, and Crystalline Metals and Alloys. The scope of this online conference is to bring together well-known worldwide experts who are currently working on Crystals to provide an online forum for presenting and discussing new results. The present report will start by providing an overview of the keynote speeches and the main axes around which the communication sessions revolve before moving on to more detailed abstracts, presenting each of the topics presented during the IOCC 2024 conference.

1. Conference Introduction

The 4th International Online Conference on Crystals (IOCC 2024), chaired by Prof. Dr. Alessandra Toncelli, was held online from 18 to 20 September 2024. It was organized by MDPI and MDPI journal Chemistry Proceedings, containing the following topics:

• S1. Liquid Crystals
• S2. Crystal Engineering
• S3. Inorganic Crystalline Materials
• S4. Organic Crystalline Materials
• S5. Hybrid and Composite Crystalline Materials
• S6. Materials for Energy Applications
• S7. Crystalline Metals and Alloys

There were seven speakers invited to give speeches in the conference. Please find the details at https://sciforum.net/event/iocc2024?subscribe&section=#event_speakers.

2. Liquid Crystals

2.1. The Universe in a Liquid Crystalline Droplet

Samo Kralj ¹, Damjan Dovnik ², Maha Zid ³, Milan Svetec ⁴, Sasa Harkai ², Iztok Babič ² and Charles Rosenblatt ⁵

¹ 

University of Maribor

² 

Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia

³ 

Solid State Department, Jozef Stefan Institute, Ljubljana, Slovenija

⁴ 

Pomurje Science and Innovation Centre, Murska Sobota, Slovenia

⁵ 

Case Western Reserve University, Cleveland, OH, USA

There is strong evidence that many natural phenomena could be described using geometrical approaches. Consequently, it is of interest to identify experimentally accessible systems in which the universality of geometry-based approaches could be tested or/and investigated in detail. Testbed laboratory systems (i.e., analogues) could serve as gateways toward a deeper understanding of phenomena in other ways, such as experimentally inaccessible systems that are mathematically related to such analogues.

Diverse liquid crystalline (LC) phases and configurations are ideal candidates for such purposes. These optically anisotropic soft matter representatives combine properties of ordered crystals and liquids and exhibit a rich diversity of different symmetries. Their states could be well described by mesoscopic molecular fields, which could be easily manipulated by diverse external stimuli, and the resulting field-configurations could be probed using relatively simple and inexpensive optical methods (e.g., optical polarizing microscopy).

In our presentation, we intend to illustrate how phenomena studied in LCs could be exploited to obtain insight into open problems of particle physics and cosmology. In particular, we address (i) the Kibble–Zurek mechanism describing coarsening dynamics of the Higgs field in the early universe, (ii) the stabilization and manipulation of skyrmion-family structures (these quasiparticle configurations were originally proposed to describe hadrons and mesons), and (iii) the stabilization and manipulation of fermionic Weyl-type excitations. We also (iv) illustrate analogues of “virtual particles” and suggest a possible origin of (v) dark matter and (vi) of the asymmetry between “particles” and “antiparticles” in the Universe.

2.2. Investigation of the Phases and the Nature of the Corresponding Phase Transition of a Chiral Ferroelectric Liquid Crystalline Compound

Barnali Barman

• Department of Physics, Seva Bharati Mahavidyalaya, Jhargram, West Bengal, India, 721507

Liquid crystals offer an excellent platform for studying the nature of phase transitions by providing a rich variety of mesophase orderings [1]. In many cases, they occur in narrow temperature ranges, and the phase transitions between different mesophases can be either continuous or weakly first-order. The most commonly studied mesophases are nematic (N), smectic-A (SmA), smectic-C (SmC), and their chiral analogues, such as N*, SmA*, and SmC* phases. This work mainly focuses on the characteristics of the N* to SmC* phase transition of a pure ferroelectric liquid crystalline (FLC) compound, namely QVE 8/5 [2,3]. The textures are characteristics of the different phases. For the studied compound, the characteristic textures corresponding to the N* and SmC* phases have been detected. The optical transmission method [4,5] has been used in order to investigate the N* to SmC* phase transition. The temperature variation of the transmitted intensity for the compounds QVE 8/5 have been measured for both planar and homeotropic alignments of the molecules. The critical behaviour of the N* to SmC* phase transition has also been investigated. The extracted critical exponent (α′) of the investigated compound was found to be less than 0.5, which implies the second-order nature of the N*–SmC* phase transition corresponding to the studied FLC compound.

2.3. Exploring Optical Properties of Nematic Liquid Crystals Dispersed with Perovskite Quantum Dots

Ankita Sutar ¹, Shital Kahane ¹ and Swapnil Doke ²

¹ 

Department of Physics, Dr. Vishwanath Karad MIT World Peace University, Pune, India

² 

Centre for Materials for Electronics Technology (C-MET), Pune, India

This study demonstrates the enhancement in photoluminescence (PL) of nematic liquid crystals (NLCs) doped with CsPbBr3 (perovskite) quantum dots (QDs). These perovskite QDs significantly boost the PL intensity by improving the anisotropic nature of NLC molecules, thereby reducing light leakage centres and intrinsic defects. Two different sizes of QDs were synthesised using a wet chemical method. X-ray diffraction (XRD) confirmed the orthorhombic crystallite structure of the QDs, while transmission electron microscopy (TEM) determined their size as 5.5 (±0.98) nm and 10 (±1.8) nm. The optical features of QDs were investigated by recording absorption and emission spectra at room temperature, which revealed unique excitonic peaks at 479 and 513 nm, whereas emission was seen at 503 and 518 nm for two different sizes, respectively. These highly luminescent QDs were further used to enhance the emission of NLC. Initially, liquid crystal (LC) sample cells were fabricated using the conventional polyimide technique, followed by the incorporation of NLC-QD composites via capillary action. The prepared sample cells were then characterized using polarizing optical microscope (POM) images and PL spectra measurements. The intensified dark state and brightened bright state POM images demonstrate improved unidirectional alignment along with a homogeneous texture of the NLC-QD composite. This improvement in molecular alignment, coupled with the reduction in light leakage centres and defects, is reflected in the PL spectra, showing an increased emission intensity of 18% for the 10 nm sized sample. The enhanced emission of NLCs is attributed to the modified dielectric anisotropy in the presence of QDs. Conversely, 5.5 nm NLC–QD composites led to increased light leakage centres in the POM dark state and a subsequent reduction in PL intensity. The results indicate that these QDs are ideal for fabricating QD-based display devices with enhanced optical contrast, making them a promising choice for next-generation display technologies.

2.4. Molecular Simulation of the Phase Behaviour of Attractive Rod-like Polymers

Daniel Martínez-Fernández, Alberto Sevilla, Miguel Herranz, Katerina Foteinopoulou, Nikos Ch. Karayiannis and Manuel Laso

• ETS Ingenieros Industriales/ISOM, Universidad Politécnica de Madrid, Madrid, Spain

Through a hierarchical modelling scheme, we determine a phase diagram of attractive rod-like polymers in three dimensions, comparing them with their freely jointed polymer counterparts [6,7]. Rod-like polymers are modelled as linear chains of tangent hard spheres whose chain stiffness is governed by a tuneable harmonic potential for the bending angle [8]. Employing the Simu-D suite [9], extensive Monte Carlo simulations provide a surprisingly rich collection of distinct crystal polymorphs, which can be finely tuned according to the range of attraction. These crystal polymorphs, identified by the Characteristic Crystallographic Element (CCE) norm [10], include face-centred cubic, hexagonal close-packed, simple hexagonal, and body-centred cubic structures and their combinations, as well as the establishment of the Frank–Kasper phase for freely jointed chains. Furthermore, employing the concept of cumulative neighbours of ideal crystals, a simple geometric model is proposed as a function of the range of attraction to accurately predict most of the observed structures and the corresponding transitions [7]. A geometrical analysis is provided of the characteristics of the self-assembled polymer clusters and crystals under conditions corresponding to a vacuum. Therefore, the present study demonstrates, at a fundamental level and in a highly idealised model, the capacity to fine-tune a single interaction parameter to be employed for the design of polymer crystals with tailored morphologies.

2.5. Local and Global Order in Two-Dimensional Packings of Semi-Flexible Polymers

Daniel Martínez-Fernández, Clara Pedrosa, Miguel Herranz, Katerina Foteinopoulou, Nikos Ch. Karayiannis and Manuel Laso

• ETS Ingenieros Industriales/ISOM, Universidad Politécnica de Madrid, Madrid, Spain

Dense packings of semi-flexible polymer chains are researched through the Monte Carlo suite Simu-D [9] in extremely confined monolayers, effectively corresponding to two-dimensional films [11]. We systematically study the effect of chain stiffness on the packing ability and the emergence of local and global orders of semi-flexible polymers, modelled as linear chains of tangent hard spheres, the chain stiffness of which is tuned by a harmonic bending potential [8]. Thus, the limit of random close packing (RCP) is explored as a function of the equilibrium bending angle, while the local and global order of the emergent structures is quantified by the degree of crystallinity [10] and the nematic and tetratic orientational order parameters [12], respectively. A multi-scale wealth of structural behaviour is observed for the different semi-flexible systems studied, which is inherently absent in packings of athermal individual monomers and is surprisingly richer than that in three dimensions under bulk conditions. As a general trend, an isotropic to nematic transition is observed at sufficiently high surface coverages. As surface coverage further increases, the nematic phase is followed by the establishment of a tetratic state, which in turn marks the onset of RCP. For chains with right-angle bonds, the incompatibility of the imposed bending angle with the neighbour geometry of the triangular crystal (the densest structure in two dimensions) leads to a singular intra- and inter-polymer tiling pattern made of squares and triangles. The present study could serve as a step towards the design of hard colloidal polymers with tuneable behaviour for 2D applications.

2.6. Modeling the Kinetics of Auto-Oscillations in a Nematic Liquid Crystal Cell with Photoaligning in an Azo-Dye Layer on a Substrate

Ivan I. Yakovkin ¹, Mykhailo F. Ledney ¹ and Andrii B. Nych ²

¹ 

Physics Faculty, Taras Shevchenko National University of Kyiv

² 

Department of Molecular Photoelectronics, Institute of Physics of the NAS of Ukraine

Azo-dye layers have shown great promise due to the possibility of obtaining noncontact photoalignment layers of high quality. In this study, we investigate a structure that consists of a nematic liquid crystal (NLC) cell, in which one of the substrates is covered with a photosensitive azo-dye layer. The NLC has an initial planar director orientation. The linearly polarized light falls normally on the surface of the cell and propagates through the liquid crystal, reaching the azo-dye layer and interacting with it. The interaction of the light with the azo dye leads to reorientation of the molecules of the azo dye perpendicular to the light polarization. This changes the boundary condition for the NLC director and can result in its reorientation to a twisted state. Considering the NLC cell parameters that facilitate the Mauguin regime, the same photoalignment mechanism then kicks in in a perpendicular direction, leading to oscillations of the boundary conditions for the director and of the NLC director profile.

The dynamics of the NLC director reorientation are modelled using the free-energy formalism, and the reorientation of the azo-dye molecules is modelled within the 2D Brownian orientation diffusion model. It was established that when the incident light intensity reaches a threshold value, the induced photo-alignment of the azo dye becomes sufficient to start the NLC director reorientation toward a π⁄2 twist state. The threshold intensity increases with the Frank elastic constant and decreases with the anchoring energy. An increase in the light intensity and the azo-dye intermolecular interaction coefficient and a decrease in the viscosity of the NLC director lead to faster transitions between states and a lower period of oscillations.

2.7. Self-Avoiding Rotating Walks as Models of Crystals Made of Freely Rotating Polymers in Two Dimensions

Carlos González-Chamorro Sánchez, Cédric Loussert, Ismael Alati Benhammou, Javier Benito and Nikos Ch. Karayiannis

• Universidad Politécnica de Madrid

The concept of random walk (RW) [13] and its variation in the form of the self-avoiding random walks (SAWs) [14] are important tools in studying complex processes in a wide variety of fields, including, among others, polymer physics. Recent molecular simulations on extremely confined, monolayer films made of athermal semi-flexible polymers have revealed a wealth of structural behaviour as a function of surface coverage chain stiffness, in the form of the equilibrium bending angle [15]. Inspired by this and to quantify the thermodynamic stability of the two-dimensional polymer crystals, we map them into self-avoiding rotating walks (SARWs), restricted to follow the geometric constraints of the corresponding lattices. For a reference crystal, and by selecting a compatible equilibrium bending angle, we enumerate all possible configurations of single-chain crystals and calculate the corresponding size distribution as a function of the number of steps. SARW enumeration has been performed on honeycomb, square, and triangular lattices, all being characterized by different coordination numbers and lattice connectivity. The scaling of the number of SARWs, as well as their average size, as a function of steps are fitted using exponential-power-law asymptotic expressions and critical amplitudes; the connective constant and the critical exponents are compared against the analogous ones for conventional SAWs, corresponding to freely jointed polymers, under the same conditions [16,17].

2.8. CB-Based Plasmonic Nanomaterials

Karolina Ordon, Olga Kaczmarczyk and Katarzyna Matczyszyn

• Wrocław University of Science and Technology

Arranging plasmonic nanomaterials in a certain way can create materials with special optical properties, such as having anisotropy with refractive indices of simultaneously opposite signs for opposite light polarization. This type of material can be based on doping a liquid crystal system with nanoparticles with the indicated properties. Gold nanorods (AuNRs) are rod-shaped nanoparticles with size-dependent optical responses, and because of their plasmonic properties, they are used in imaging and fluorescent enhancement.

In our work, we investigated the influence of gold nanorods on the phase transitions and optical properties of the liquid crystal 8CB, known for its thermotropic behaviour. Gold nanorods were synthesised using a seed-mediated approach to obtain nanoparticles with the desired dimensions (aspect ratios: 5.6; 8.2; 10.8), which were observed and measured using transmission electron microscopy. Different concentrations of AuNRs were added to the 8CB samples, which were then inserted into liquid crystalline cells. All the samples were observed under a polarized light microscope equipped with a heating stage. At each concentration of the AuNRs, different optical structures were observed in both the nematic and smectic phases. The temperatures of the phase transitions also differed depending on the amount of the AuNR dopant in the system. The observed changes obtained by doping 8CB-based systems with nanoparticles may lead to the design of new metamaterials.

2.9. Molecular Simulation Studies of the Isotropic-to-Nematic Transition of Rod-like Polymers in the Bulk and Under Confinement

Biao Yan, Daniel Martínez-Fernández, Katerina Foteinopoulou and Nikos Ch. Karayiannis

• Universidad Politécnica de Madrid

In this research work, we conduct extensive Monte Carlo simulations to investigate the factors that affect the isotropic-to-nematic transition [12,18] of hard colloidal polymers in bulk and under various conditions of confinement. Polymers are represented as linear chains of tangent hard spheres of uniform length, with the stiffness being controlled by a bending potential, leading to rod-like configurations [8]. Confinement is realized through the presence of flat, parallel, and impenetrable walls in one, two, or three dimensions [19], and periodic boundary conditions are applied in the unconstrained dimensions. All simulations are performed through the Simu-D software, composed of conventional and advanced, chain-connectivity-altering Monte Carlo algorithms [9].

The local and global structure of the computer-generated system configurations are gauged through the Characteristic Crystallographic Element (CCE) norm [10] and the long-range (nematic) order parameter [12]. Distinct factors, including chain length and stiffness, confinement and packing density are found to profoundly affect the isotropic-to-nematic transition at the level of chains and the establishment of close-packed crystallites at the level of monomers.

2.10. Thermally Stabilizing and Tuning Photonic Liquid Crystal Phases with Nanoparticles

Omar Aljohani ^1,2 and Ingo Dierking ¹

¹ 

Department of Physics & Astronomy, University of Manchester.

² 

Department of Physics, Taibah University.

Photonic liquid crystal (LC) phases, such as blue phases (BPs) and the cholesteric phase (ChP), have contributed to a variety of photonic devices due to their three-dimensional and one-dimensional photonic band gaps (PBGs), respectively. These phases exhibit a helical periodic structure, which functions as a PBG that selectively reflects circularly polarized light (CPL). Tuning the PBG by adjusting its pitch length and extending the thermal stability and design applications of these phases have been significant research objectives over the last decade. Recently, a promising approach for thermally stabilizing blue phases and tuning the PBG to fabricate novel devices involve dispersing nanoparticles (NPs) into liquid crystal hosts that exhibit BPs and ChPs. In this study, various nanoparticles, including Al₂O₃, BaTiO₃, C60, and cellulose nanocrystals (CNCs), were dispersed into two liquid crystal hosts, a thermochromic mixture (TLC), and mixtures of cholesteryl nonanoate (CN) with nematic MBBA at different concentrations, to investigate their effects on the thermal stability and tunability of the PBG. The results demonstrate clear evidence of the extension of the BPs’ thermal stability and the tuning of their PBG pitch. Notably, BPs exhibited greater thermal stability during cooling than during heating, which is an indication of increased supercooling effects. Furthermore, an increased cooling rate proportionally enhanced the thermal stability of the BPs, likely because of supercooling phenomena. Additionally, although BPs do not require alignment, their selective reflection was enhanced by introducing planar alignment. Moreover, enhanced tuning of the pitch length was observed when NPs were added to the BPs and ChP compared to the pure LC host. The thermal stability improvements and enhanced tuning of the PBG suggest potential for developing more robust photonic devices, particularly for lasing and smart window applications.

2.11. Liquid Crystal–Ferrofluid Emulsions

Varun Chandrasekar, Ingo Dierking and Jian Ren Lu

• Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK

Dispersing nanoparticles in liquid crystals (LCs) is used to tune liquid crystal properties, to add functionality, or to exploit the self-organization of the liquid crystals to transfer order onto dispersed particles. Dispersing ferrofluid droplets into liquid crystals (LCs) not only adds magnetic functionality to the LCs but also produces unique systems. Magnetic functionality can be used to measure the anisotropic viscosities of the LCs on a microscopic scale when moving the ferrofluid inclusions through various thermotropic, lyotropic, and colloidal LCs using an external magnetic field. The magnetite nanoparticles of the ferrofluid form a boundary layer at the interface between the LC and the ferrofluid droplets. The viscosities are calculated using Stokes’ Law, together with the introduction of the boundary layer at the LC–ferrofluid interface. The viscosities for a variety of different liquid crystalline systems were measured as a function of changing environment, such as temperature, concentration, or pitch.

In nematic LCs, ferrofluid droplet chains are formed due to the topological defects in the LC induced by the dispersed ferrofluid droplets. The movement of these chains can be controlled by the external magnetic field. The velocities of water-based ferrofluid droplet chains in nematic 5CB, while varying factors such as the average size of the droplets, the number of droplets in the chain, and the external magnetic field strength, are reported. Adding a surfactant to the LC–ferrofluid emulsions enables the production of ferrofluid droplet chains uncoated with a membrane in the LC. A comparative study between the behaviour of the LC–ferrofluid emulsion with the addition of the surfactant polysorbate 60 (Tween-60) and uncoated ferrofluid droplet chains is reported. Different surfactants and lipids are used to produce membranes around the ferrofluid droplets to create a synthetic structure which mimics a magnetotactic bacterium.

2.12. Design Method of a Variable-Focus-Length Lens Employing a Liquid-Crystal-Loaded Metasurface

Seiji Fukushima ¹, Keitatsu Nakamura ², Tsutomu Nagayama ², Toshio Watanabe ² and Hirotsugu Kikuchi ³

¹ 

Kagoshima University

² 

Graduate School of Science and Engineering, Kagoshima University

³ 

Institute for Materials Chemistry and Engineering, Kyushu University

We have reported a demonstration of light beam steering by using a liquid-crystal-loaded metasurface (LC-MS), which was based on voltage-controlled refractive index distribution on the metasurface. We can upgrade a beam-steering device to a variable-focal-length lens by introducing parabolic refractive index distribution on LC-MS. Moreover, the focal length is controllable by voltage across the liquid crystal. We show the design method of the variable-focal-length lens and their numeric demonstrations in this paper.

The proposed lens model is one-dimensional and has parabolic refractive index distribution. In designing the device, we employed two procedures of theoretical far-field pattern (FFP) calculation and computer-based electromagnetic near-field pattern (NFP) simulation. The FFP calculation was carried out by means of phase calculation on the basis of classic optics. The results indicated the estimation of the lens effect although the preciseness of the focal length was not assured since the number of pixelated LC-MS was too small to evaluate the phases and steering direction of light beams. Then, our next strategy is electromagnetic field (EMF) simulation using a COMSOL simulator that can calculate the EMF near the pixelated LC-MS. The simulation results improve by repeating these two processes. As a result, we found that LC-MS functions as a lens, and the focal length is variable. The focal length was controllable within approximately 2.2 times, assuming a maximum refractive index change of 0.1, a pixel number of 11, and a wavelength of 600 nm.

To conclude, we established a design method of a variable-focal-length lens that employs LC-MS. The controllability of the focal length and the lens function were numerically demonstrated. This kind of LC-MS device does not require high voltages in general. Experimental demonstrations would be our next study.

2.13. Liquid Lecithin Crystals as Carriers of Biologically Active Substances and Nanoparticles

Mariia Mikhailovna Zoshchik, Mariia Alexandrovna Safronova and Natalia Mikhailovna Murashova

• D. Mendeleev University of Chemical Technology of Russia

Lecithin liquid crystals are promising carriers for transdermal drug delivery. They are able to include both lipophilic and hydrophilic substances, as well as solid particles. In this work, liquid crystals in a system comprising lecithin, avocado oil, tea tree oil, and water, containing biologically active substances and nanoparticles, were studied.

It was shown that in the range of shear rates from 0.01 to 1.0 s⁻¹, the introduction of 1.0 and 3.0 mol/L NaCl aqueous solutions increased the viscosity of the liquid crystals, on average, by 4 and 9.1 times in comparison with the control sample. The introduction of potassium chloride glucosamine sulphate solutions with mass concentrations of 50, 100, and 150 g/l increased the viscosity by 1.3, 2.2, and 3.3 times, while the introduction of 1 wt.% albumin in a citrate buffer solution into the liquid crystalline sample increased its viscosity by 1.5 times.

The addition of 0.3 wt.% of CuO nanoparticles (92 ± 3 nm) increased the viscosity by 2.0 times and that of CuSO₄ aqueous solution by 2.5 times compared with the control sample. When 0.3 wt.% of CuO microparticles (31.2 ± 3.5 mm) was added, the viscosity decreased by 1.3 times. The kinetics of the release of copper ions from liquid crystals (copper content 2.4 mg/g) by dialysis were studied at T = 37 °C. The release rate of Cu²⁺ for liquid crystals with the CuSO₄ solution was 7.6 · 10⁻⁴ g/(m² · h); for CuO nanoparticles, it was 5.86 · 10⁻⁴ g/(m² · h); and for microparticles, it was 2.36 · 10⁻⁴ g/(m² · h). Therefore, a dimensional effect was observed. This difference can be explained by the fact that copper ions in liquid crystals with CuSO₄ are already in the solution, but for samples with CuO particles, their dissolution is required.

The results obtained will help in the development of medical products based on lecithin liquid crystals.

2.14. The Effect of Liquid Crystal Electrolyte Modification on the Efficiency of Organic Photovoltaic Cells

Stanisław Różański and Paweł Szubert

• Stanisław Staszic State University of Applied Sciences in Pila

In many modern devices used to convert or store electricity, such as dye-sensitized solar cells (DSSCs), fuel cells, lithium-ion batteries or supercapacitors, one of the critical elements is the organic electrolyte, the stability and physicochemical properties of which significantly affect the efficiency of the processes of converting or storing electrical energy. The essence of the concept of using liquid crystals in such devices is that properly ordered structures at the nanometer scale lead to an increase in ionic conductivity in a specific direction and fulfil the role of stabilizing the system mechanically and thermally. Moreover, temperature induction of phase transitions enables switching off functions in a given electrolytic structure.

DSSCs with porous semiconductor titanium dioxide (TiO₂) electrodes were sensitized using ruthenium-based dyes purchased from Solaronix. In this experiment, the following ruthenium dyes were used: cis-diisothiocyanato-bis (2.2′-bipyridil-4.4′-dicarboxylic acid) ruthenium (II), known as N3; cis-diisothiocyanato-bis (2.2′-bipyrida-4, 4′-dicarboxylato) ruthenium (II) bis(tetrabutylammonium), marked as N719; and the amphiphilic ruthenium dye cis-diisothiocyanato-(2.2′-bipyridil-4.4′-dicarboxylic acid)-(2.2′-bipyridil-bipipyridil-4.4′-dinonyl) ruthenium (II), known in the literature as Z907. The electrolyte (AN-50) with a low viscosity contained iodide/tri-iodide as a redox couple, and a redox concentration of 50 mM was used.

The current–voltage (I-U) characteristics were determined for the ruthenium-based dyes mentioned above in order to check the influence of their structure on the efficiency of the DSSC cells. Next, it was checked what effect the addition of a nematic liquid crystal of 4-cyano-4′-pentylbiphenyl (5CB) to the iodide electrolyte had on the I-U characteristics. Modification of the I-U characteristics was found, in particular a change in the values of ISC current and UOC voltage.

3. Crystal Engineering

3.1. Hydrogen Bonds Between Coordinated Water Molecules: A Crystallographic and Density Functional Study

Isidora Janković and Dušan Malenov

• University of Belgrade—Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia

Hydrogen bonds are the most abundant noncovalent interactions of water molecules. Previous studies have shown that the strength of the water–water hydrogen bond (−5.0 kcal/mol) increases if one of the water molecules coordinates to transition metal (−9.7 kcal/mol). One of the indicators of this strengthening is the shortening of H∙∙∙O hydrogen bond distances in the crystal structures deposited in the Cambridge Structural Database (CSD).

To study how the coordination of both water molecules influences their hydrogen bonds, we used the ConQuest program to screen high-quality crystal structures deposited in the CSD. The contacts between two aqua ligands in these crystal structures were accepted as hydrogen bonds if the O∙∙∙O distance was shorter than 4.0 Å and the O-H∙∙∙O angle was bigger than 110°. The energies of hydrogen bonds were calculated using the B97D/def2-TZVP level of theory.

The majority of the obtained hydrogen bonds have H∙∙∙O distances between 1.8 Å and 2.0 Å, which is longer than hydrogen bonds between coordinated and free water (1.6–1.8 Å). Although this might point towards the weakening of hydrogen bonds by the coordination of both water molecules, the DFT calculations show that the energy of a single hydrogen bond between aqua ligands reaches −11.0 kcal/mol, most likely due to increased dispersion effects. We found that the observed increase in the lengths of hydrogen bonds between aqua ligands is induced by the size of aqua complexes and their tendency to form multiple simultaneous hydrogen bonds. Our DFT calculations show that the supramolecular structures with multiple hydrogen bonds between aqua ligands reach an interaction energy of −70.0 kcal/mol.

This study implies that the coordination of both water molecules further increases the strength of their hydrogen bonds and shows that hydrogen bonds between aqua ligands are significant contributors to the stability of supramolecular systems of metal complexes.

3.2. C-H/O Interactions of Aromatic Ligands in Organometallic Compounds—Crystallographic and Density Functional Study

Milica Jakovljević and Dušan Malenov

• University of Belgrade—Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia

C-H/O interactions are among the most abundant weak hydrogen bonds due to the omnipresence of C-H groups and oxygen atoms. Previous studies have shown that coordination with metals can cause the strengthening of noncovalent interactions, such as hydrogen bonds, stacking interactions, cation–π, and anion–π interactions. In this work, we studied the influence of transition metal coordination on C-H/O interactions of aromatic ligands in organometallic complexes.

Crystal structures of high quality, deposited in the Cambridge Structural Database (CSD, version 5.43, November 2022), were studied using the ConQuest program (version 2022.3.0) to find C-H/O interactions between the η⁶-coordinated benzene and the oxygen atom of a Z₁-O-Z₂ fragment, where Z₁ or Z₂ could be any atom. The contact was accepted as a C-H/O interaction if the O∙∙∙H distance was shorter than 2.9 Å and the C-H∙∙∙O angle was bigger than 110°. The density functional theory was employed to calculate the energies of C-H/O interactions.

Our CSD search resulted in 152 C-H/O interactions of coordinated benzene, mostly in organometallic half-sandwich compounds. The analysis of geometrical parameters shows that preferred O∙∙∙H distances in these interactions are between 2.3 Å and 2.5 Å. These O∙∙∙H distances are shorter for coordinated than uncoordinated aromatic rings, indicating that coordinated aromatic rings form stronger C-H/O hydrogen bonds than uncoordinated ones. These findings are confirmed by our preliminary B3LYP-D3/aug-cc-pVDZ calculations, which showed that in the organometallic half-sandwich model system Cr(C₆H₆)(CO)₃∙∙∙H₂O, the C-H/O interaction reaches the energy of −3.88 kcal/mol, which is considerably stronger than the C-H/O interaction between (uncoordinated) benzene and water (−1.64 kcal/mol).

Our joint crystallographic and computational study points towards the enhanced ability of coordinated aromatic rings to form substantial C-H/O interactions. This study provides further insights into the strengthening of noncovalent interactions via transition metal coordination.

3.3. O-H...O and O-H...N Hydrogen Bonds as Supramolecular Syntons in the Formation of Chiral Architectures on Thiazolo [3,2-a]Pyrimidine 2-Arilmethylidene Derivative Frameworks in the Crystalline Phase

Mariya Mailyan ¹, Artem Agarkov ², Elina Gabitova ^1,2, Anna Nefedova ², Alexander Ovsyannikov ², Igor Litvinov ², Svetlana Solovieva ² and Igor Antipin ¹

¹ 

Department of Organic and Medical Chemistry, Kazan Federal University, Kremlevskaya 18, 420008 Kazan, Russia

² 

Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzova 8, 420088 Kazan, Russia

The synthesis of new antitumor drugs is a promising direction in modern science. Currently, some thiazolopyrimidine derivatives are already known to exhibit different antitumor activities. Since the biological activities of racemate and pure enantiomers of many biologically active compounds may greatly differ from each other, the question of their separation, i.e., obtaining them in enantiopure form, is a pressing one.

Non-covalent interactions may be important for understanding the mechanism of drug action and can also be used in crystallization to separate racemic mixtures into pure enantiomers. Since a racemic mixture is formed during the synthesis of thiazolo[3,2-a]pyrimidine derivatives, the study of these derivatives in the crystalline phase is an essential problem.

This work is devoted to the synthesis and study of the supramolecular organization of new thiazolo[3,2-a]pyrimidine derivatives in the crystalline phase. The structure of all obtained compounds was characterized by IR, NMR ¹H and ¹³C spectroscopy, ESI-MS spectrometry, and SCXRD analysis.

The influence of the synthesised derivatives’ structure and the used solvent’s nature on the supramolecular motif of their organization in the crystal phase due to the presence of O-H...N- and O-H...O-type hydrogen bonds was established.

The majority of derivatives containing the o-vanillin fragment form racemic dimers. Derivatives containing a 4-hydroxybenzylidene fragment form zigzag homochiral chains. When derivatives containing a 2-hydroxybenzylidene fragment crystallize, bridging hydrogen O-H...N and O-H...O bonds are produced with a solvate molecule. It causes the formation of zigzag homochiral chains in the crystalline phase.

The crystallization of derivatives containing 2-methoxyphenyl with 2-hydroxybenzylidene and phenyl with 2-hydroxy-3-methoxybenzylidene moieties, respectively, from ethanol resulted in the formation of conglomerates.

3.4. Non-Covalent Structure-Forming Bonding of 2-aryhydrazone thiazolo[3,2-a]pyrimidines in the Crystalline Phase

Dilyara Mingazhetdinova ¹, Artem Agarkov ², Anna Nefedova ³, Alexander Ovsyannikov ², Igor Litvinov ², Igor Antipin ^2,4, Svetlana Solovieva ^1,2

¹ 

Kazan Federal University, A.M. Butlerov Chemical Institute, 18 Kremlevskaya St., 420008 Kazan, Russia

² 

Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzova 8, 420088 Kazan, Russia

³ 

Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Arbuzova 8, 420088 Kazan, Russia

⁴ 

Kazan Federal University, A.M. Butlerov Chemical Institute, 18 Kremlevskaya St., 420008 Kazan, Russia

Currently, hydrazones are promising building blocks for the creation of various supramolecular architectures since they can undergo conformational and configuration changes under the influence of external conditions. Thus, from the point of view of supramolecular chemistry, the potential use of compounds containing a hydrazone functional group for the design of molecular switches, as well as for the creation of new materials, has been demonstrated.

This work is devoted to the synthesis and study of 2-arylhydrazone thiazolo[3,2-a]pyrimidine derivatives structures in the crystalline phase.

The obtained derivatives are characterized using a complex of physico-chemical (IR, NMR ¹H, and ¹³C spectroscopy; ESI-MS spectrometry; and X-ray diffraction) analyses.

It was confirmed that arylhydrazones are in the Z-isomer form in the crystalline phase. Additionally, it was established that non-covalent intramolecular and intermolecular interactions play the main role in supramolecular organization in crystals. So, the formation of hydrogen-, chalcogen-, π-π-bonded racemic dimers, and halogen-bonded homochiral chains was shown.

The structure of arylhydrazones containing halogen substituents in aryl fragments has also been studied. The embedding of a sterically inaccessible halogen substituent, blocked for the formation of intermolecular interactions, into one of two aryl fragments that switch off the action of structure-forming halogen bonding in one position and switch on in the second one together leads to different self-assembly in the crystalline phase.

Thus, the synthesis and study of the supramolecular organization of 2-arylhydrazone thiazolo[3,2-a]pyrimidine derivatives in the solid phase were successfully carried out, and the possibility of implementing various supramolecular ensembles was discovered.

3.5. Coordination Polymers as Functional Materials

Andrzej Kochel ¹, Małgorzata Hołyńska ² and Kamil Twaróg ¹

¹ 

University of Wrocław, Faculty of Chemistry, ul. F. Joliot-Curie 14 Wrocław, Poland

² 

2ESA/ESTEC, Keplerlaan 1, 2201AZ Noordwijk, The Netherlands

The advanced synthesis of coordination polymers is fascinating due to its resulting structural diversity and vast opportunities to design new functional magnetic materials.

The physicochemical properties of coordination polymers result from a combination of synthesis conditions and properties of simple, well-known precursors [20,21,22]. This generates the possibility to model the electrical, magnetic, and optical properties of coordination polymers. These could find application as luminescent materials, catalysts, sensors, ion exchangers, and as magnetic materials. An important research topic in recent years is the luminescent properties of these materials. In comparison with organic compounds that are used, e.g., in the manufacturing of OLED-type diodes, inorganic coordination compounds prevail as they possess a much higher thermal stability, widening the operational temperature range.

Depending on the valence electrons’ configuration, the luminescent properties of coordination polymers are governed by MLCT (metal–ligand charge transfer), LMCT (ang. ligand–metal charge transfer), LLCT (ang. ligand–ligand charge transfer), or IL (ang. inter-ligand charge transfer) states.

Herein, we present novel coordination polymers based on copper ions and organic aminocarboxylate ligands. For these compounds, the complexation of copper ions results in the amplification of emissions and an increase in the maximum emission shift.

3.6. Is Bridging Water in Metal Complexes the Strongest Hydrogen Bond Donor? Crystallographic and DFT Insights

Dušan Petar Malenov

• University of Belgrade—Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia

Arguably the most famous type of noncovalent interactions, hydrogen bonds are very important in numerous chemical and biological systems, including the ones with aqua complexes. Metal coordination enhances the strength of hydrogen bonds of water by amplifying the positive charge on interacting hydrogen atoms. In this work, the hydrogen-bonding ability of water molecules acting as bridging ligand in metal complexes was studied by the means of crystallographic analysis, as well as density functional calculations.

A survey of crystal structures of high quality from the Cambridge Structural Database (CSD) was performed using the ConQuest program to find hydrogen bonds between bridging water in metal complexes as a hydrogen bond donor and the water molecule as a hydrogen bond acceptor. The energies of hydrogen bonds found in the CSD were calculated in the Gaussian 09 suite of programs using the dispersion-corrected B97D density functional and the def2-TZVP basis set.

A total of 88 hydrogen bonds of bridging water in metal complexes was found. The majority of these hydrogen bonds have short H∙∙∙O distances, mostly between 1.7 Å and 1.9 Å, with several examples even below 1.6 Å. Additionally, these hydrogen bonds possess a high degree of linearity, with the majority of O-H∙∙∙O angles between 165° and 175°. These geometrical parameters indicate short and linear, and therefore strong, hydrogen bonds. DFT calculations show that these interactions are indeed very strong. Specifically, neutral complexes containing bridging water form hydrogen bonds with free water that can reach an energy of −15.4 kcal/mol. This is significantly stronger than hydrogen bonds of neutral metal complexes of non-bridging water, which do not surpass −10.0 kcal/mol.

The joined crystallographic and computational study demonstrates the enhanced ability of bridging water in metal complexes to act as hydrogen bond donor.

3.7. Polymorphism in Riluzole Salts and Cocrystals with Aromatic Carboxylic Acids

Alexander P. Voronin ¹, Anna G. Ramazanova ² and German L. Perlovich ²

¹ 

G.A. Krestov Institute of Solution Chemistry of Russian Academy of Sciences, Ivanovo, Russia

² 

G. A. Krestov Institute of Solution Chemistry of Russian Academy of Sciences, Ivanovo, Russia

In this work, we investigated the influence of positional isomerism on the packing arrangements and the hydrogen bond network in multicomponent crystals of the drug riluzole with hydroxybenzoic acids. A combined theoretical/experimental study, including virtual screening, X-ray diffraction, IR/Raman spectroscopy, thermal analysis, and periodic DFT computations, was conducted to isolate and identify the novel crystal forms. By surveying multicomponent crystals of riluzole deposited in the Cambridge Structural Database, we found that salicylic acid derivatives with pKa 3.8 form salts with riluzole, while benzoic acid derivatives without ortho-hydroxyl groups form cocrystals. New multicomponent crystals of riluzole with salicylic, 4-hydroxybenzoic, 2,3-, 2,4-, and 2,6-dihydroxybenzoic acid were obtained and structurally characterized. Varying the experimental conditions allowed us to isolate samples of metastable polymorphs of salts with salicylic, 2,4-, and 2,6-dihydroxybenzoic acids. For Form II of the riluzole + 2,6-dihydroxybenzoic acid salt, the crystal structure was determined based on data on powder diffraction of high-energy synchrotron radiation. The hydrogen bond network was found to be identical in riluzole 2,6-dihydroxybenzoate Form I and Form II, and the difference was limited to the mutual orientation of hydrogen-bonded layers, which is a rare example of packing polymorphism. The metastable form was found to undergo an irreversible phase transition at about 120 °C, visible as an exothermal event on the thermogram. For riluzole salicylate, two polymorphic modifications were discovered in addition to the already reported form, and the stability relationship between them was studied based on DSC, HSM, and dissolution studies. In addition, solvated salt forms were found in the systems with 2,4- and 2,6-dihydroxybenzoic acids during slurry experiments in water, dioxane, and DMSO. For the newly obtained phases and pure components, their solubility was determined in aqueous buffer solutions at different pHs and organic solvents, and salt formation thermodynamic functions were obtained from the thermodynamic cycle.

3.8. Screening Conditions for the Synthesis of Crystalline Spherical Clusters Using 5-Hydroxynicotinic Acid

Catarina Veríssimo Esteves

¹ 

Centro de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal

² 

LAQV-REQUIMTE, Chemistry Department, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal

³ 

Departamento de Engenharia Química e Biológica, Escola Superior de Tecnologia do Barreiro, Instituto Politécnico de Setúbal

Crystallization is used for product separation and purification in production sectors such as food, agriculture, electronics, and pharmaceuticals [23]. However, a considerable lack of understanding about the molecular mechanisms behind the formation of crystals remains. Systematic solubility and crystallization studies on families of compounds are useful to understand how slight changes in molecular structure can impact the crystallization outcome. Building upon previous studies on the hydroxynicotinic acid family [24,25], in this work, novel insights into the optimization of synthetic procedures to obtain crystalline spherical clusters of 5-hydroxynicotinic acid (5HNA) are presented. This work meticulously explores and identifies the most favourable conditions for producing spherical clusters of 5HNA. The systematic screening of various synthetic conditions has led to the successful formation of these clusters. This work opens up new avenues for the potential applications of 5HNA spherical crystalline clusters. Such clusters have diverse diameters depending on the solvent and the synthesis conditions. The clusters were characterized by means of optical microscopy, scanning electron microscopy (SEM), and powder X-ray diffraction (PXRD). The clusters were possibly formed through a self-assembly process driven by hydrogen bonding and π–π interactions between the 5HNA molecules. The solvents ought to play a relevant role in such a self-assembly process. The clusters exhibit different crystallinity depending on the solvent. Such clusters could be used as building blocks for nanomaterials with potential applications in a multitude of fields.

4. Inorganic Crystalline Materials

4.1. Study of Synthesized Molecular Chiral Lactam Structures for Volatile Compound Profile Enrichment Using Gas Chromatography–Mass Spectrometry (GC-MS) Technique

Isaya Thaveesangsakulthai ¹ and Sorrawit Songsathitmetha ²

¹ 

Faculty of Science, Chulalongkorn University

² 

Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand

In a study of the chiral enantiomer structure of cyclic trilactams possessing C3 symmetry, the dimer structure was established through the formation of three NH···O-type complementary H-bonds at three amides, which were applied as agents for volatile compound profile extraction in a sample via the liquid phase extraction technique.

The extraction efficiency of cyclic trilactam materials for analytes found in perfume samples was assessed using HS-SPME-GC-MS. The experimental arrangement of perfume solution was combined with the materials in EtOH solvent in an open vial, while the perfume in EtOH (without the materials) served as the control. Following overnight evaporation at room temperature, the remaining liquid was collected for HS-SPME-GC-MS analysis. Extraction took place overnight to explore the materials’ extraction efficiency and facilitate re-crystallization. The materials underwent re-crystallization, with the collected crystals revealing a similar shape to the observed dimers. This suggests a robust hydrogen-bonding interaction within the dimer and the volatile compounds interacting. A list of identified compounds during extraction was compiled for each material and the control. The enrichment peak areas in the chromatogram results were determined as the analyte peak area in the sample containing the materials to the area of the same analyte in the control. This indicated the extraction performance of volatile analytes in the sample containing the materials compared with the control sample, such as Linalylformate (5.1 ± 0.015) × 10⁷, Citronellol (5.1 ± 4.2) × 10⁶, Carvone (4.2 ± 3.5) × 10⁵, Linalylacetate (2.5 ± 2.2) × 10⁷, and α-Terpinylacetate (2.3 ± 1.7) × 10⁵ of the main potential compounds. Higher enrichment signifies stronger interactions between the analytes and these materials.

The solubility between the compounds in less polar solvents can be attributed to their structural features and the nature of the solvent. Specifically, the solubility of each compound is influenced by factors such as polarity, hydrogen-bonding capability, and the molecular size and shape of the compounds can influence their interactions with the solvent molecules, further impacting solubility differences between compounds in less polar solvents.

4.2. Influence of the Seed-Layer Material on the Direct Growth of Zinc–Tin Oxide (ZTO) Nanostructures

Ana Rovisco, Jorge Martins, Elvira Fortunato, Rodrigo Martins, Rita Branquinho and Pedro Barquinha

• CENIMAT/i3N, Department of Materials Science, NOVA School of Science and Technology (NOVA-FCT) and CEMOP/UNINOVA, NOVA University Lisbon, Campus de Caparica, 2829-516 Caparica, Portugal.

Recently, metal oxide nanostructures have seen significant advancements in synthesis and device integration. Considering the sustainability of materials and processes, as well as multifunctionality, zinc–tin oxide nanostructures are among the most promising oxide nanostructures being researched. Their ternary oxide nature allows for impressive multifunctionality, with applications including catalysis, electronics, sensors, and energy harvesting. To synthesise these materials, the use of seed layers can be beneficial since they can influence the growth of nanostructures and are advantageous for applications where nanostructures on film are desired, such as photocatalysis and sensors.

In this work, several seed layers (namely Cu, stainless steel, Cr, Ni, etc.) were tested for the synthesis of ZTO nanostructures. It was generally observed that the structures grown on the seed layers differed from those obtained with the seed-layer-free hydrothermal method (under similar synthesis conditions [26,27,28]), demonstrating the effectiveness of seed layers in influencing growth. Various types of structures were obtained, such as ZnSnO₃ nanowires and Zn₂SnO₄ nanoparticles, octahedrons, and nanowires. The results suggest a correlation between the phase of the employed seed layer and the resultant phase of the nanostructures. Furthermore, it was generally seen that while shorter times favoured the production of nanostructures, longer times resulted in thin films with a nanostructured surface when employing the seed layers [29]. This emphasizes the influence of seed layers on nanostructure growth, not only by inducing the phase but also by accelerating the growth process.

4.3. Sodium Polymolybdates Grown by Low-Thermal-Gradient Czochralski Technique for Scintillating Applications

Veronika D. Grigorieva, Anastasia Bondareva and Marina Artemyeva

• Nikolaev Institute of Inorganic Chemistry SB RAS

The presented work is dedicated to the search of new perspective scintillating materials for rare events physics, particularly neutrinoless double beta-decay projects. Such implementations impose strict requirements on scintillator quality and radioactive background. Most bivalent cations have radioactive isotopes; thus, light alkali cations are better-fitted for this purpose. Moreover, due to their small ionic radii, Li and Na are less substituted by U and Th.

Another issue with obtaining crystals for scintillation purposes is the minimal working size of the element—40*40 mm³—while maintaining uniformity in entire bulk volume. We propose the low-thermal-gradient Czochralski technique (LTG Cz) developed at NIIC SB RAS as a unique technology for obtaining bulk oxide crystals of high optical quality. Temperature gradients in LTG Cz compared to the conventional Czochralski technique are two orders of magnitude lower, less than 1 deg/cm.

In the literature, several versions of Na₂O-MoO₃ phase diagrams are presented, stating stable compounds Na₂MoO₄, Na₂Mo₂O₇, and Na2Mo4O13 (impossible for obtaining because of polymorphic phase transition) and in different works, Na₄Mo₉O₂₉, Na₆Mo₁₀O₃₃, and Na₆Mo₁₁O₃₆. The space group of the compound Na₆Mo₁₁O₃₆ was determined on powder samples as triclinic. In the presented work, Na_xMo_yO_z crystals were grown using the LTG Cz technique. The space group of Na₆Mo₁₁O₃₆ crystal sample was determined as monoclinic.

Acknowledgements

This work was supported by the Russian Science Foundation № 23-23-10068 and Novosibirsk Region Grant № p-49 (https://rscf.ru/project/23-23-10068).

4.4. Chemical Equitable Partitions of Inorganic Lattices

Vasilios Raptis

• Department of Computer Science and Engineering, School of Sciences, European University Cyprus, 6 Diogenes Str., Nicosia 2404, Cyprus

Introduction. Graph-theoretical approaches in the study of materials can shed new light on their structure–property relationships. Here, a novel concept termed Chemical Equitable Partition (CEP) [30,31] was used as a means to look at crystal symmetries and classify atoms accordingly.

Methods. The study focused on inorganic perovskites and oxides, without partial or mixed occupancies. Atom pairs were marked as adjacent when the sum of the atoms’ radii exceeded the pair distance, respecting unit-cell periodicity. Atom radii proposed by Alvarez [32] were used (occasionally rescaled to reproduce coordination numbers). The atoms’ connectivity profiles were processed as described by Michos and Raptis [33] to derive Chemical Equitable Partitions. Electrostatic lattice site potentials were calculated using VESTA’s [34] built-in functionality. CEP cells were compared to the atom groups defined by Wyckoff positions, on the one hand, and site potentials, on the other.

Results. Highly symmetric cells featured identical partitions, according to CEP, Wyckoff positions, and Madelung potentials, whereas CEP in systems with lower symmetry was a refinement of the partitions with respect to electrostatic potentials and Wyckoff positions.

Conclusions. CEP provides an alternative perspective on crystal structure and symmetry. Forthcoming research will specify how CEP seamlessly incorporates organic moieties, as found in hybrid organic/inorganic crystals, within a unifying framework.

4.5. Use of Boron-Doped Nanocrystalline Diamond Microelectrodes for Amperometric Determination of Serotonin Release in Human Platelets

Rosalía González-Brito ^1,2,3, Pablo Montenegro ^1,2, Alicia Méndez ^1,2, Ramtin E. Shabgahi ⁴, Alberto Pasquarelli ⁴, Ricardo Borges ^1,2

¹ 

Pharmacology Unit, Medical School, Universidad de La Laguna. Spain

² 

Instituto Fundación Teófilo Hernando, Madrid, Spain

³ 

Organic Chemistry Department, Universidad de La Laguna, Spain

⁴ 

Institute of Electron Devices and Circuits, Ulm University, Germany

Introduction. Boron-doped nanocrystalline diamond (BDD) is an outstanding structure, and one of the best materials for high-sensitivity amperometric measurements. Nanocrystalline diamond structures show a high concentration of electrical charge carriers.

Amperometry is a widely used technique for studying the exocytosis of biological amines (dopamine, serotonin, noradrenaline, adrenaline, and histamine), and multielectrode array (MEA) systems have increased the efficiency and speed of amperometric studies.

In humans, platelets are the most accessible cells to study the exocytosis of serotonin.

Methods. BDD-MEA fabrication utilizes several processes typical of microelectronics, here including chemical vapor deposition (CVD), optical lithography, metal evaporation, and reactive ion etching (RIE).

We detected amperometric recordings from the quantum release of serotonin from human platelets with boron-doped nanocrystalline diamond on MEA systems (BDD-MEA) of 16 microelectrodes. Our studies were carried out with devices on silicone matrices (BDD-on-silicon MEA) [35] and quartz substrates (BDD-on-quartz MEA) [36].

Results. Typical amperometric signals were obtained from the release and subsequent oxidation of serotonin molecules stored in platelet vesicles. We carried out and compared the release measurements both under basal conditions and after loading the platelets with 10 µM serotonin for 2 h. In this communication, we show different types of peaks registered in these studies, and we present kinetics parameters obtained with both types of MEA systems (maximum oxidation current, spike width at half maximum, spike net charge, and ascending slope of spike) [35,36].

Conclusions. BDD MEA devices have proven to be effective and biologically compatible in amperometric studies with live platelets. Here, we demonstrate their usefulness in studies of serotonin exocytosis from human platelets.

4.6. Investigation of the Structural, Microstructural, Optical, and Electrical Properties of Iron-Doped Barium Titanate Ceramics

Driss Akhlidej, Abdelhalim Elbasset, Farid abdi and Taj-dine Lamcharfi

• Signals, Systems and Components Laboratory, University Sidi Mohammed Ben Abdellah USMBA, Faculty of Science and Technology of Fez, BP 2202, Route d’Imouzzer, Fez, Morocco

The structural, microstructural, optical, and electrical properties of nanoceramic BaTi_1-xFe_xO_3-δ synthesised via sol–gel have been investigated. The X-ray diffraction analysis demonstrates that samples have a single-phase tetragonal structure with P4mm symmetry. This result was confirmed using the Rietveld method. Infrared spectroscopic analysis (FTIR) shows the presence of two bands at 490 cm⁻¹ and 2358 cm⁻¹, corresponding to T-O and C=O, respectively. On the other hand, the scanning electron microscopy (SEM) results show that nanoceramics sintered at 1250 °C have a spherical grain morphology. The grain size is small at X = 0.02 and increases progressively thereafter. The UV–vis absorption spectrum confirms the influence of Fe concentration on the direct optical band gap of BaTi_1−xFe_xO_3−δ ceramics. The optical band gap shifts from 2.63 eV to 2.35 eV. Making this material a good candidate for solar photocatalytics. There is an increase in Urbach energy as the Fe concentration increases from 0 to 0.4. On the other hand, the AC conductivity of the materials is subject to Joncher’s law. The effect of Fe substitution concerns the decrease in conductivity at x = 0.02 and then increases. The Cole–Cole complex impedance diagram was studied for the prepared samples. The compounds showed non-Debye-type dielectric relaxation, with a poor grain radius as Fe-doping increased.

4.7. New Quaternary Chalcogenides Ag₁₁D^IVC^III₃S₁₂

Lyudmyla Piskach, Orysia Berezniuk, Lubomir D Gulay and Yuri M Kogut

• Department of Inorganic and Physical Chemistry, Lesya Ukrainka Volyn National University, Lutsk, 43025, Ukraine

Ternary and quaternary silver chalcogenides are promising semiconductor materials for practical use that possess various valuable physical properties, such as optical, electric, ferroelectric, and ionic conductivity. Antimony chalcogenides are of interest to the research for thermoelectric properties and optical absorption suitable for thin-film solar cells. Our investigation combined these two directions in the quasi-ternary systems Ag₂S–C^III₂S₃–D^IVS₂ (C^III–Sb, As; D^IV–Ge, Sn), where three new quaternary sulphide compounds were found, Ag₁₁GeSb₃S₁₂, Ag₁₁SnSb₃S₁₂, and Ag₁₁SnAs₃S₁₂.

Alloys of the systems were synthesised by co-melting the elements at up to 1220 K, slow cooling to 500 K, annealing for 500 hrs, followed by quenching. Ag₁₁GeSb₃S₁₂ forms at the intersection of AgSbS₂–Ag₈GeS₆ and Ag₃SbS₃–Ag₂GeS₃; Ag₁₁SnSb₃S₁₂ forms at the intersection of AgSbS₂–Ag₈SnS₆ and Ag₃SbS₃–Ag₂SnS₃; and Ag₁₁SnAs₃S₁₂ forms at the intersection of AgAsS₂–Ag₈SnS₆ and Ag₃AsS₃–Ag₂SnS₃. In all cases, the component ratio is 3:1. X-ray phase analysis and microstructure studies show that each compound has a modest homogeneity region of up to 5 mol.%.

The crystal structure of Ag₁₁GeSb₃S₁₂ was investigated by X-ray structural analysis. The diffraction dataset was recorded at a DROM 4-13 powder diffractometer, CuKα radiation, angle range 10° ≤ 2Θ ≤ 100°, scan step 0.02°, and 10 s exposure in each point. The diffraction pattern of Ag₁₁GeSb₃S₁₂ was indexed in the cubic symmetry, space group I3m, and lattice parameter a = 0.54127(2) nm. Sulphur atoms form three-layer closest packing, the statistical mixture of Ag and Ge atoms occupies one half of the octahedral voids, and Sb atoms occupy one quarter of the tetrahedral voids.

Further investigation of the crystal structure of two other compounds as well as the study of optical absorption and electrophysical properties to quantify the prospects of these compounds as materials is pending.

4.8. Developments, Features, and Perspectives of Crystal Scintillators of the Cs₂MCl₆ family (M = Hf or Zr) to Search for Rare Processes

Alice Leoncini ^1,2, Pierluigi Belli ^1,2, Rita Bernabei ^1,2, Fabio Cappella ^3,4, Vincenzo Caracciolo ^1,2, Riccardo Cerulli ^1,2, Antonella Incicchitti ^3,4, Matthias Laubenstein ⁵, Vittorio Merlo ², Serge Nagorny ^6,7, Viktoriia Nahorna ⁸, Stefano Nisi ⁵ and Peng Wang ⁷

¹ 

Dipartimento di Fisica, Università di Roma “Tor Vergata”, 00133 Rome, Italy

² 

INFN, Sezione di Roma “Tor Vergata”, 00133 Rome, Italy

³ 

INFN, Sezione di Roma, 00185 Rome, Italy

⁴ 

Dipartimento di Fisica, Università di Roma “La Sapienza”, 00185 Rome, Italy

⁵ 

INFN Laboratori Nazionali del Gran Sasso, 67100 Assergi, AQ, Italy

⁶ 

Department of Physics, Engineering Physics and Astronomy, Queen’s University, Kingston, ON K7L 3N6, Canada

⁷ 

Arthur B. McDonald Canadian Astroparticle Physics Research Institute, Kingston, ON K7L 3N6, Canada

⁸ 

Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6, Canada

Recently, there has been considerable interest in the development of crystal scintillators of the Cs₂MCl₆ family of metal hexachlorides (M = Hf or Zr) due to their exceptional properties: high light yield (up to 40,000 photons/ MeV), good linearity in the energy response, excellent energy resolution (3.5% at 662 keV in the best configuration), and excellent ability to discriminate between pulse shapes (PSD) of β(γ) and α particles. One Cs₂HfCl₆ (CHC) crystal scintillator was measured, over 2848 h of data taking, deep underground in the STELLA laboratory at the Gran Sasso National Laboratory of the INFN, Italy. Its residual radioactive contaminants were studied and are presented here. The total α activity of the detector was at the level of 7.8(3) mBq/kg. A measurement using two Cs₂ZrCl₆ (CZC) crystal scintillators (11 g and 24 g) was performed in the DAMA/CRYS low-background setup deep underground at LNGS. Chemical purity, residual radioactive contaminants, scintillation, and PSD performance are discussed in this paper. The low-background measurements over 456.5 days demonstrated the crystals’ high radiopurity, showing a counting rate of 0.17 (kg·keV·y)⁻¹ at the Q_2β = 3.35 MeV of ⁹⁶Zr. Another measurement was subsequently carried out using three new CZC crystals and one CHC crystal in optimized geometry. The crystal growth technique, raw material purification, and post-growth material treatment are discussed here. Moreover, the three CZC crystals were grown using starting materials with different purities to study their resulting characteristics and were encapsulated using a silicone-based sealant. The results obtained are presented in this paper.

4.9. The Synthesis and Characterization of a Metal–Organic Framework Based on N,N′-Dioxide for the Selective Adsorption of Iodine Anions

Ksenia Abasheeva and Pavel Demakov

• Nikolaev Institute of Inorganic Chemistry SB RAS

Introduction. This study presents the synthesis and characterization of a new metal–organic framework (MOF) incorporating cobalt(II) and 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide (odabco), namely [Co₂(H₂O)(NO₃)(odabco)₅](NO₃)₃. The anion substitution reaction in the framework has been studied, and the adsorption selectivity and reversibility of the iodide ions with this compound have been investigated.

Methods. Synthesis: A mixture of Co(NO₃)₂·6H₂O (0.10 mmol) and odabco·3H₂O₂ (0.30 mmol) was prepared in a glass vial. The mixture was dispersed in a solution of DMF (5.0 mL), water (0.4 mL), and nitric acid (25 μL, 62%). The mixture was kept at 70 °C for 72 h. The crystal structure of the compound was confirmed using powder X-ray diffraction (PXRD) analysis. The chemical purity of the sample was verified using CHN analysis, infrared (IR) spectroscopy, and thermogravimetric analysis (TGA).

Ion exchange was studied using capillary zone electrophoresis (CZE). The iodide positions within the porous adsorbent were determined by single-crystal XRD. The structural integrity of the samples was verified using XRD and other methods.

Results. The cationic coordination network was found to exhibit a high affinity for iodide, and the degree of substitution of the guest nitrates by iodides was 75%. The iodide positions were directly determined by a single-crystal XRD method within an anion-exchanged adduct, [Co₂(H₂O)(NO₃)(odabco)₅]I₂(NO₃)·1.85H₂O. The adsorption of iodide is selective and reversible. The iodide anions occupied specific positions within the network, stabilized by the aliphatic core of the odabco ligands. The incorporation of iodide into the pore structure stabilizes it and has the potential to effectively remove iodide from solutions.

Conclusions. This study emphasizes the significance of MOFs for addressing challenges related to selective ion sorption and has potential applications in environmental management and health protection. Further research into similar systems and modifications may lead to the development of improved adsorbent materials for removing ions from solutions.

4.10. Preliminary Structural Characterization of Ceria–Titania Polymorphic Mixtures Achieved by High-Energy Ball Milling

Matías Gastón Rinaudo ¹, Luis Eduardo Cadús ² and Maria Roxana Morales ²

¹ 

INTEQUI-CONICET, Universidad Nacional de San Luis (UNSL), San Luis, Argentina

² 

Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Universidad Nacional de San Luis (UNSL), Facultad de Química Bioquímica y Farmacia, Almirante Brown 1455, Capital, 5700 San Luis, Argentina

High-energy ball milling is a simple and eco-friendly technique that has gained increasing popularity in recent years. This one-pot method of synthesis allows for the preparation of solid materials from a green perspective, avoiding multiple and complex steps, the use of solvents, and the extreme pressure and temperature conditions commonly employed. Due to its multiple advantages, high-energy ball milling can make structural and surface modifications within the solid matrix according to the physicochemical properties needed, such as defect accumulation, polymorphic transformations, grain boundaries, amorphization, particle refinement and increases in specific surface area and ion mobility. In this regard, ceria–titania mixtures were obtained using several high-energy ball milling conditions (varying the metal oxide concentration, ball-to-powder ratio, time and rotational speed). The crystal structures created by the milling process were studied by means of X-ray Powder Diffraction (XRPD), including cerianite, anatase, rutile, and high-pressure TiO₂ (II) formation. Moreover, the crystallite sizes and the specific surface area (S_BET) values were estimated using the Scherrer equation and N₂ physisorption (BET method), respectively. According to this preliminary study, the materials generated through this sustainable, cost-effective, and easy-to-scale technique could be useful as catalyst supports for different metal nanoparticles or could act as catalysts in a variety of applications, e.g., oxidation and photocatalytic reactions in both the liquid and gas phases.

4.11. The Influence of the Counterion in the Behavior of a Trans-Diacetate Dysprosium Complex with a Semirigid Macrocycle

Cristina González-Barreira ¹, Julio Corredoira-Vázquez ^1,2,3, Matilde Fondo ¹, Ana M. García-Deibe ¹, Jesús Sanmartín-Matalobos ^1,3

¹ 

Departamento de Química Inorgánica, Facultade de Química, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain

² 

Phantom-g, CICECO—Aveiro Institute of Materials, Department of Physics, University of Aveiro, 3810-193—Aveiro, Portugal

³ 

Institute of Materials (iMATUS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain

Introduction. After studying the magnetic properties of [Dy(L)(OAc)₂]NO₃·2H₂O (L = 2E,6E,9E,13E-3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane-2,6,9,13-tetraene), its single-molecule magnet behaviour under an optimal field of 2000 Oe was revealed. Furthermore, luminescence measurements indicated that the ratio between the integrated intensity of the macrocyclic Schiff base and that of the Dy^{3+ 4}F_9/2 → ⁶H_13/2 transition can define a secondary luminescent thermometer, with a maximum relative thermal sensitivity value of 2.3% K⁻¹. In view of these interesting properties, we changed the counterion from nitrate to tetraphenylborate to see its influence.

Synthesis and methods. Here, we present the result of the synthesis and characterization of the dysprosium complex [DyL(OAc)₂]BPh₄. It was obtained by a template synthesis of 2,6-pyridinedicarboxaldehyde, dysprosium acetate tetrahydrate, and ethylenediamine, and a subsequent reaction with sodium tetraphenylborate. Single crystals of the compound were obtained via the recrystallization of the solid in dichloromethane with an Et₂O layer in the fridge. Then, it was characterized by elemental analysis, IR spectroscopy, and single X-ray diffraction techniques.

Results. Two slightly different moieties of [DyL(OAc)₂]⁺ are present in the unit cell, alongside tetraphenylborate anions, but no other species are present. Thus, the crystal packing lacks classic H bonds, whereas many C-H···O and C-H···π interactions are present in the crystal-packing scheme. This cationic complex shows a decacoordinate metal centre, almost forming a distorted tetradecahedron. The characterization of this Dy^III complex allows us to compare its properties with those of other closely related species.

Conclusion. The presence of such a hydrophobic counterion strongly influences the crystal packing of this species, but it does not have such an intense impact on other features, mostly related to the [DyL(OAc)₂]⁺ cation.

4.12. The Influence of the Substitution in Cation and Anion Sublattice on the HT-Pb₂GeS₄ Structure

Oleksandr Smitiukh, Oleg Marchuk and Andrew Korzhov

• Lesya Ukrainka Volyn National University

Abstract: The HT-Pb₂GeS₄ (SG I-43d) is a prospective material for investigation. The structure of HT-Pb₂GeS₄ crystallizes in cubic symmetry. The positions 24d, 16c, and 48e can be modified through the substitution of atoms Pb and S. We investigated the crystalline structure of four compositions, Pb_1.9Sn_0.1GeS_3.52Se_0.48, Pb_1.86Sn_0.14GeS_3.32Se_0.68, Pb_1.82Sn_0.18GeS_3.16Se_0.84, and Pb_1.58Sn_0.42GeS_3.64Se_0.36, changing the cation and anion sublattice simultaneously.

Samples with the nominal compositions of Pb_2−xSn_xGeS_4−ySe_y (x = 0.1, 0.14, 0.18, and 0.42; y = 0.36, 0.48, 0.68, and 0.84) were prepared by melting high-purity Pb (shot, 99.99%), Sn (shot, 99.99%), Ge (shot, 99.999%), S (shot, 99.99%), and Se (shot, 99.99%) in quartz containers evacuated to a residual pressure of 10⁻² Pa. The total mass of every sample was 1 g. The ampules with the stoichiometric mixtures of elements were heated up to 1423 K at a rate of 12 K/h; kept at this temperature for 4 h; cooled down to 773 K at a rate of 12 K/h; annealed at this temperature for 500 h; and quenched in cold water without breaking the containers.

The substitution in cation and anion sublattice on the Pb₂GeS₄ crystal structure leads to the increase in the volume of the lattice from 2794.9 Å to 2852.2 Å due to the change in y. The lattice parameter a changes from 14.086 Å to 14.1816 Å. A distortion of the cation sublattice is also observed.

Hence, such peculiarities of the crystal structure may improve some thermoelectric and optical properties.

4.13. Formation of a Semiconductor State in Oxysulfostibnite RSbS₂O with R = Gd, Dy, Ho, and Er

Semyon Timofeevich Baidak ¹, Alexey Vladimirovich Lukoyanov ^2,3

¹ 

M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences

² 

M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, Ekaterinburg, Russia

³ 

Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia

The features of the semiconducting-state formation in oxysulfostibnites of the rare earth metals GdSbS₂O, DySbS₂O, HoSbS₂O, and ErSbS₂O have been investigated. Our theoretical calculations were performed in the framework of the GGA+U method, accounting for strong electron correlations in the 4f shell of rare earth metals, and they showed that these compounds, GdSbS₂O [37], DySbS₂O, HoSbS₂O, and ErSbS₂O, are semiconductors with a small direct gap at high-symmetry point X. For the first time, it was found that for the band gap formation in the rare-earth-metal oxysulfostibnites, it is important both to optimize the crystal structure and to take into account the spin–orbit coupling. The rare-earth-metal oxysulfostibnites, along with their layered structural analogues oxysulfides, due to their distinctive properties, can be widely used in biomedicine, photoluminescence, and other fields. Our calculations were performed on the Uran supercomputer at the Institute of Mathematics and Mechanics of the Ural Branch of the Russian Academy of Sciences. This research was carried out within the framework of the state assignment of the Ministry of Education and Science of Russia, theme “Electron”, No. 122021000039-4.

S.T. Baidak, A.V. Lukoyanov, “Semimetallic, half-metallic, semiconducting, and metallic states in Gd-Sb compounds”, International Journal of Molecular Sciences 24, 8778 (2023), https://doi.org/10.3390/ijms24108778.

4.14. Bite Angle Assessment of Coordination Geometry of Zinc(II) 2,2′-Bypiridine Crystal

Ayodele Temidayo Odularu ¹, Peter Adewale Ajibade ² and Johannes Xanoxolo Mbese ¹

¹ 

Department of Chemistry, University of Fort Hare, Alice 5700, Eastern Cape, South Africa.

² 

University of KwaZulu-Natal, School of Chemistry and Physics, Pietermaritzburg Campus, South Africa.

Literature reports of zinc(II) 2,2′-bipyridine crystal in chemistry journals by different researchers call for urgent attention because of its significance in catalysis, drug delivery, electrochemistry, materials chemistry, nanomedicine, and nanotechnology. Here, different coordination geometries reported include tetrahedral, octahedral, distorted tetrahedral, distorted octahedral, and square pyramidal geometries. Outside other forms of characterization, there are techniques of bite angle, such as computational chemistry and nuclear magnetic resonance (NMR); this study considered the concept of bite angle determined experimentally from X-ray crystallography. This led to the following research question: “how does the bite angle assess the different coordination geometries of zinc (II) 2,2′crystal reported in the literature of Chemistry journals?”. In response to this question, qualitative research was used as the methodological approach to explore how the ligand field theory (LFT) supports the bite angle’s assessment of the coordination geometry of zinc(II) 2,2′crystal using X-ray crystallography from recently reported literature in top-rated chemistry journals. Results showed how bite angles of similar zinc(II) 2,2′crystal compared with LFT to validate the reported coordination geometry of zinc(II) 2,2′-bipyridine crystal. The implication of this study is to enhance the relevance and importance of bite angles in zinc(II) 2,2′crystal.

4.15. Interfacial Action of Co-Doped MoS₂ Nanosheets on the Directional Piezoelectric Catalytic Generation of Reactive Oxygen Species

Win Thi Yein ^1,2,3 and Wang Qun ³

¹ 

Department of Industrial Chemistry, University of Yangon, Yangon, Myanmar

² 

Department of Environmental Science and Engineering, Ewha Womans University, New 11-1, Daehyeon-dong, Seodaemun-gu, Seoul 120-750, Republic of Korea

³ 

School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China

Molybdenum disulfide (MoS₂) with single- and odd-numbered layers is a novel piezocatalyst, and its piezocatalytic molecular oxygen activation, which produces reactive oxygen species (ROS), has been considered a promising and low-cost strategy for environmental remediation. However, its performance is still far from satisfactory, and the limited knowledge regarding its molecular oxygen activation process significantly impedes its further development. Herein, several numbered layers of Co-doped MoS₂ ultrathin nanosheets (UNs) with a thickness of 3.2 nm were successfully fabricated via hydrothermal synthesis. The single Co-atom-doped odd-numbered layers of MoS₂ nanosheets strongly interacted with adsorbed oxygen molecules for a highly efficient generation of ROS in the piezocatalytic degradation process. The dopant-induced enhanced carrier density (electron density) of Co-doped MoS₂ was 7.7 × 10¹⁸ cm^−3, compared with 2.9 × 10¹⁶ cm⁻³ for bare MoS₂. Moreover, the interfacial action of Co-doped MoS₂ nanosheets on directional molecular oxygen activation properties were predicted by DFT calculation and monitored by generated reactive oxygen species (ROS) evolution. Co-doped MoS₂ decomposed tetracycline (an antibiotic) by 99.8% in 15 min through shaking vibration in the dark. It was found that Co-active sites can facilitate the one-electron reduction in molecular oxygen activation by introducing a Co²⁺/Co³⁺ redox couple. In addition, a tentative mechanism was proposed to explain the origin of the piezocatalytic enhancement in Co-doped MoS₂. Thus, in order to meet the requirements in the field of wastewater pollutant remediation, the current research effort may provide guidelines for constructing 2D TMDCs piezoelectric catalysts and comprehending the mechanisms of the directional piezoelectric catalytic generation of reactive oxygen species through the doping route.

4.16. Effect of Extract Concentration and Temperature on Microstructural Properties of Biological ZnO Nanoparticles

Luis Alfonso García-Cerda ¹, A.G. Nuñez-Briones ², I. Vera-Reyes ¹ and B.A. Puente-Urbina ¹

¹ 

Centro de Investigación en Química Aplicada, Blvd. Enrique Reyna Hermosillo 140, 25294 Saltillo, Coahuila, México

² 

Facultad de Sistemas, Universidad Autónoma de Coahuila, Carretera a México Km 13, 25350, Arteaga, Saltillo, Coahuila, México

Due to their diverse properties, zinc oxide nanoparticles (ZnONPs) have shown great potential in various applications. These nanoparticles exhibit unique characteristics, including antimicrobial, anti-inflammatory, wound healing, catalytic, magnetic, optical, and electronic properties, making them useful in various fields. The size and crystalline structure of the material are crucial factors affecting these properties. In recent years, using plant extracts to synthesise nanoparticles has emerged as a technique that allows for the control of the size, shape, and properties of these materials. The main objective of this work is to study the influence of extract concentration and temperature on the synthesis of ZnONPs using Flourensia cernua extract. Zinc nitrate hexahydrate was used as a precursor, and we tried different extract–solvent ratios, such as 0.5:10 and 1:10 w/v. The ZnNPs were synthesised at varying temperatures ranging from 300 to 500 °C. ZnONPs were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectrometry (FTIR). The XRD patterns showed a wurtzite hexagonal phase of ZnO. According to TEM characterization, crystalline particles with a semi-spherical morphology were obtained in a size range between 10 and 22 nm. Interestingly, increasing the amount of extract led to a decrease in the particle size. On the other hand, an increase in the calcination temperature caused the growth of the nanoparticles. This method showed that extract concentration and temperature greatly influence the size of the ZnONPs. The application of these particles in the photodegradation of organic dyes is being studied. Using plant extracts as a green synthesis method for ZnONPs can provide a sustainable and eco-friendly approach to developing customized nanoparticles for various applications.

4.17. The Peculiarities of the Crystal Structure of the Monoclinic Modification of Aragonite

Olga Kazheva ¹, Sergey Aksenov ² and Ivan Vasilenko ¹

¹ 

Peoples’ Friendship University of Russia named after Patrice Lumumba, Institute of Biochemical technology and nanotechnology, Miklukho-Maklaya str.10 b. 2, 117198 Moscow, Russia

² 

Laboratory of Arctic Mineralogy and Material Sciences, Kola Science Centre, Russian Academy of Sciences, 14 Fersman str., 184209 Apatity, Russia

The crystallization and precipitation of calcium carbonate minerals is the subject of intensive research due to the existence of its polymorphic and morphological varieties in geological and biological systems, as well as due to its application both in industrial fields, in particular, in the production of plastics, rubbers, and paper production, and for the creation of biomedical implants and drug delivery systems.

The existence of a new polymorphic modification of calcium carbonate, monoclinic aragonite CaCO₃, has been experimentally discovered. Its crystal structure has been solved, and its crystal structure has been discussed. It was found that, unlike the previously known modification, orthorhombic aragonite with cell parameters a = 4.961 Å, b = 7.967 Å, and c = 5.740 Å, the new polymorph belongs to monoclinic symmetry, crystallizes in the space group P2₁/c, and has cell parameters a = 12.732 Å, b = 5.740 Å, c = 9.378 Å, and b = 96.91°.

The crystal cell of the new polymorph is formed by three Ca²⁺ cations and three carbonate anions occupying general positions. In the structure, carbonate anions form stacks along the b axis, in which they are arranged in a mutually overlapping manner. The stacks are surrounded by Ca²⁺ cations coordinated by nine oxygen ions. The new monoclinic polymorph has pseudohexagonal symmetry, and this effect is observed only along the b direction of the cell and is absent in the direction of other axes. As in the case of vaterite, the existence of a supercell can be assumed in the structure of the new aragonite, resulting in the high R-factor.

A three-dimensional set of diffraction reflections was obtained for a single crystal at room temperature using a Rigaku OD XtaLAB Synergy-S single-crystal diffractometer on MoK_α radiation (λ = 0.71073 Å). The experimental data were processed using the CrysAlisPro v. 1.171.39.46 software package. The crystal structure was determined based on direct methods using the SHELX software package.

4.18. Green Synthesis of Zinc Oxide Nanoparticles Using Itsit (Trianthema portulacastrum) Extract and Their Catalytic Activity

Afia Aleem, Naveed Ahmad and Munawar Iqbal

• Department of Chemistry, University of Education, Faisalabad Campus, Pakistan 38000

Green synthesis of nanoparticles is more promising versus chemical and physical methods, as it is environmentally friendly, cost-effective, and non-toxic. Considering environmental sustainability, this study was designed to explore Itsit (Trianthema portulacastrum) efficacy for green synthesis of nanoparticles. The main objective of this study was to investigate the potential of zinc oxide (ZnO) nanoparticles developed from Itsit extract, through green methods for the treatment of textile dyes. This investigation reports that using the plant extract of Itsit, synthesis of nanoparticles of zinc oxide occurs in which zinc oxide is used as a precursor. In the green method, the plant extract that includes the biomolecules is used to reduce the zinc ions into zinc atoms like ZnO nanoparticles. Flavonoids, phenolic compounds, terpenoids, alkaloids, and flavone are all plant metabolites, the potential reducing agents used for ZnO nanoparticle preparation. The zinc oxide nanoparticles were prepared and characterized through UV–visible, FT-IR, and Zetasizer. The application of nanoparticles developed for their photocatalytic potential was investigated for the decolorization of a synthetic dye, phenol red. The ZnO nanoparticles prepared from Itsit showed 38% decolorization of phenol red, showing its promising catalytic potential under sunlight. Based on these findings, it can be concluded that Itsit demonstrated promising photocatalytic potential for the remediation of textile dye and could be employed for the treatment of textile wastewater.

4.19. The Influence of an Ultra-Small Amount of Heterovalent Y³⁺ Activator Ions in Aqueous Solution on the Defect Formation of Different Growth Sectors of α-Ni²⁺SO₄·6H₂O Crystals

Irina A. Kaurova ¹, Galina M. Kuz’micheva ¹, Levko A. Arbanas ¹ and Vera L. Manomenova ²

¹ 

MIREA—Russian Technological University, Vernadsky pr., 78, Moscow, 119454, Russian Federation

² 

Federal Research Centre «Crystallography and Photonics», Russian Academy of Sciences, Leninsky pr., 59, Moscow, 119333, Russian Federation

Materials based on α-NiSO₄·6H₂O (NSH) (sp. gr. P4₁2₁2, Z = 4) are used for lithium-ion batteries and UV filters for the solar-blind range. Their performance characteristics can be varied by introducing activator ions M. The behaviour of M in NSH depends on differences in crystallochemical characteristics of Mⁿ⁺ and Ni²⁺ ions, the way of introducing M ions into the solution, and the growth sectors of the crystals. The goal of this work is to establish the distribution of Y³⁺ ions over the growth sectors of NSH:Y crystals when they are introduced into a solution in extremely small quantities (c = 10 mM).

Two crystals were grown on NSH (001) plates: NSH:Y-1—perpendicular to 001> (32 g; growth duration 144 h); NSH:Y-2—parallel to 001> (269 g; growth duration 336 h). The habit (mmm) was found for NSH:Y-1, faceted by {001}, {101}, {011}, {012}, and {110} with face areas (S_face{hkl}) {101} > {011} > {012} > {001} > {110}. In the habit (mm2) of NSH:Y-2 crystals, new faces ((102), (1$\overline{1}$2), and (1$\overline{1}\overline{1}$)) with S_face(hkl) (101) > (012) > (102) > (011) > (001) > (1$\overline{1}$2) > (1$\overline{1}\overline{1}$) > (110) also appeared. The NSH:Y-2 crystal, by its (00$\overline{1}$) face, was at the bottom of the crystallizer during growth (uneven supply of the solution).

The c, Å tetragonal crystal parameter (X-ray diffraction of powdered crystals) decreased with the decrease in Y³⁺ content (c_M, ppm—mass spectrometry), c{101} > c{102} > c{001}, consistent with crystal morphology. Defect formation can be described by the quasi-chemical reaction 0 → V_Ni^n′ + Y_i^m·and the composition (Ni²⁺_1−x[])(Y³⁺_i(x))SO₄]. In the {101}-{102}-{001} series, a decrease in Y³⁺ content is accompanied by a decrease in the Y³⁺ interstitials (Y_i^m·) and vacancies in the Ni²⁺ site (V_Ni^n′).

The compositions of the NSH:Y growth sectors, on which the functional properties depend, are important for the application of the material in the form of plates.

Funding: Ministry of Science and Higher Education of the Russian Federation, grant No. FSFZ-2024-0026.

4.20. Cone Beam Computed Tomography: Preliminary Studies on Novel Detector Schemes

Evangelia Karali, Christos Michail, George Fountos, Nektarios Kalyvas and Ioannis Valais

• Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece

Background: Cone-beam-computed tomography (CBCT) offers a comfortable breast examination accompanied by 3D breast representation, at the same or lower dose levels in comparison to classical mammography and its derivative tomosynthesis. In the case of dense breasts, it provides specialists a reliable anatomical representation towards an accurate diagnosis of breast pathologies. CBCT system detector configuration usually is based on a CsI:Tl scintillator.

Materials and Methods: The purpose of this study was to instigate novel detector schemes applied to a simulated micro-CBCT system, with a view to designing future experimental setups. The energy spectrum of the CBCT system X-ray source ranged from 10 to 40 keV. The system relied on a 360°-rotating table. Different detector materials of the same size and shape were simulated and investigated: LSO:Ce, LYSO:Ce, LuAG:Ce, GAGG:Ce, LaBr₃:Ce, LaCl₃:Ce, and CZT. A bone tissue capillary was used in order to investigate possible differences in the system’s spatial resolution. Further, a breast phantom was simulated in order to evaluate image quality, as it is derived from contrast-to noise ratios (CNRs) of specific ROIs (regions-of-interest). System simulation was based on GATE software. Images were reconstructed with FBP and OSEM. The evaluation was performed in conjunction to the standard CsI:Tl detector setup. All schemes were simulated with the same front-end electronic configuration.

Results: Image quality assessment depicted a dependence on detector material. LYSO:Ce, LuAG:Ce, GAGG:Ce, LaBr₃:Ce, and LaCl₃:Ce presented high CNRs for materials of different composition. CZT is a promising semiconductor energy converter in the case of a low-density bone tissue. Spatial resolution depends only on the reconstruction algorithm.

Conclusions: The aforementioned examined materials with increased CNRs could be an efficient alternative in a future CBCT system that will overcome further dense-breast-imaging limitations.

4.21. Effective Luminescence Efficiency and Spectral Matching of a Cerium Fluoride Crystal Scintillator with Various Optical Sensors

Vasileios Ntoupis ¹, Christos Michail ¹, Nektarios Kalyvas ¹, George Fountos ¹, Athanasios Bakas ², Ioannis Kandarakis ¹ and Ioannis Valais ¹

¹ 

Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, Athens, 12210, Greece

² 

Department of Biomedical Sciences, University of West Attica, Athens, 12210, Greece

Introduction. The aim of this study was to examine the effective luminescence efficiency (ELE) and the spectral matching of a 10 × 10 × 10 mm³ cerium fluoride (CeF₃) single-crystal scintillator with various optical sensors. Numerous investigations have shown that CeF₃ crystals have a non-proportional response to gamma rays, and they have already been successfully used in high-rate calorimetry, including the Large Hadron Collider’s high-luminosity phase experiments. However, the scintillation response of CeF₃ has not been systematically examined in the energy range covering medical imaging applications.

Methods. Measurements were performed with a CPI Inc. CMP 200 DR X-ray generator and an X-ray tube IAE SpA model RTM90HS in the range of 60–150 kVp and 63 mAs. Twenty mm of Al was added to the inner filter of the X-ray tube to simulate attenuation from a human chest. The effective luminescence efficiency (ELE) and the spectral matching (SMF) of the scintillator were examined with various optical sensors.

Results. The effective luminescence efficiency increases continuously in the examined energy range (60–150 kVp), with the maximum value (0.812 efficiency units (EU) being the S.I. equivalent μWm⁻²/(mGy/s)) at 150 kVp. With an emission maximum at 314 nm, the optimum effective efficiency was found for a multialkali photocathode (0.81 EU) and the flat-panel position-sensitive photomultiplier (PS-PMT) H8500D-03 (0.808). The corresponding spectral matching (SMF) values were equal to 0.97 for both the multialkali photocathode and the PS-PMT H8500D-03.

Conclusion. Within the examined energy range, the resulting values are considered low compared to those for typical materials used as X-ray radiation-to-light converters; thus, CeF₃ could not be used in radiological applications covering this energy range. It is possibly worth studying CeF₃ crystals at higher energies considering that the luminescence efficiency did not reach the maximum value at 150 kVp (the maximum energy of the medical X-ray tube).

4.22. The Temperature-Dependent Luminescence Efficiency of a Hygroscopic Cerium-Doped Lanthanum Bromide (LaBr₃:Ce) Single-Crystal Scintillator

Angeliki Martzakli ¹, Ioannis Valais ², Stavros Tseremoglou ¹, Nektarios Kalyvas ¹, George Fountos ¹, Athanasios Bakas ³, Konstantinos Ninos ³, Ioannis Kandarakis ¹ and Christos Michail ²

¹ 

Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, 12210 Athens, Greece

² 

Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, 12210 Athens, Greece

³ 

Department of Biomedical Sciences, University of West Attica, 12210 Athens, Greece

Background. Scintillators are used in a variety of applications, including modalities in environmental conditions of extreme temperature or radiation flux. Thus, knowledge of their luminescence performance under the influence of temperature or radiation flux is of paramount importance. In this framework, the aim of this study was to examine the influence of temperature on the luminescence efficiency of a hygroscopic cerium-doped lanthanum bromide (LaBr₃:Ce) single-crystal scintillator. The crystal output was compared with a cerium-doped lanthanum chloride (LaCl₃:Ce) crystal scintillator of equal dimensions, in similar experimental conditions.

Materials and Methods. The experimental setup comprised a CPI series CMP 200 DR medical X-ray source set to a fixed high voltage (90 kVp) to expose the sample to X-ray radiation under temperature conditions in the range of 23–154 °C. LaBr₃:Ce is an extremely efficient crystal, with a high light yield of 63,000 photons/MeV and a fast decay time (25 ns). The crystal was removed from the protective aluminium encapsulation (thickness 0.7 mm). Heating was performed using a Perel 3700-9 2000W heating gun. The temperature on the crystal surface was monitored using an Agilent Technologies U1253A digital multimetre, coupled to a U1185A thermocouple (J-Type) with a temperature probe adapter.

Results. The luminescence efficiency of LaBr₃:Ce decreases with increasing temperature, from 69.58 EU at 23.0 °C to 18.27 EU at 154 °C (EU is the S.I. equivalent μWm⁻²/(mGy/s). The corresponding values for LaCl₃:Ce were 33.14 to 17.96 EU in the temperature range from 29 to 162 °C. The room-temperature absolute efficiency of LaBr₃:Ce, with the protective aluminium encapsulation, was 50.02 EU.

Conclusions. LaBr₃:Ce is an extremely efficient crystal scintillator and knowledge of its performance in various temperatures could be useful for various applications, from medical imaging to detectors for extreme environments.

4.23. Disorder Effects in Magnetic Properties and Electronic Structure of Orthorhombic Mn₂TiGe

Evgeniy Denisovich Chernov and Alexey Vladimirovich Lukoyanov

¹ 

M.N. Mikheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, S. Kovalevskaya Str., 18, 620108 Ekaterinburg, Russia

² 

Ural Federal University named after the first President of Russia, B. N. Yeltsin, Mira Str., 21, 620002 Ekaterinburg, Russia

Heusler alloys attract much attention due to their potential application in spintronic, magneto-optical, and magnetocaloric devices [37,38,39]. In this work, we theoretically studied disorder effects in the electronic structure and magnetic properties of full Heusler Mn₂TiGe alloy, crystallized in the orthorhombic Ima2 structure within density functional theory (DFT). We calculated that Mn₂TiGe without defects exhibits metallic properties with a total magnetic value of 4.6 μ_B/f.u. and with partial magnetic moments of 3.2 μ_B/Mn, 1.3 μ_B/Ti, and 0.1 μ_B/Ge. This value is higher than the value of 1.99 μ_B/f.u., reported recently from theoretical calculations for the L2₁ phase of Mn₂TiGe [40]. In our additional calculations for Mn2TiGe with the antisite defects Mn-Ge, the total magnetic moment was decreased to 1.3 μ_B/f.u. with 0.9 μ_B/Ti and a negligible Ge moment. An almost identically low value of the total moment 1.1 μ_B/f.u. was found in Mn₂TiGe with the antisite defects Mn-Ti; in this case, the partial moments gradually decreased. The largest effect on the magnetic moment is exhibited by the antisite change between Ti and Ge because it provides further suppression of the Mn and Ti moments, causing the total magnetic moment to be equal to 0.6 μ_B/f.u. Also, in all cases, the Mn electronic states shift to lower energies, forming two peaks of states in the valence band in the electronic structure. Thus, we demonstrated that the investigated antisite disorder types result in a significant (by several times) reduction in the magnetic moment of the novel orthorhombic Mn₂TiGe alloy. This research was supported by the Russian Science Foundation, grant number RSF 22-42-02021.

4.24. Study of the Percolation Effect in the Luminescent Structure of ZnS:Cu,Br Phosphors on Improving Their Radioluminescence

Elena Vladimirovna Zelenina ^1,2, Maxim Sychov ² and Daniil Kolotinskii ³

¹ 

Khlopin radium institute, Saint-Petersburg, Russia

² 

Saint-Petersburg state institute of technology, material science department, Saint-Petersburg, Russia

³ 

Joint institute of high temperatures, Moscow, Russia

Solid-phase synthesis of ZnS-based luminescent material enclosing the associative luminescence centres formed by the dopant atoms of copper and bromine Cu’Zn-BrS● is discussed. Annealing the powder mix of ZnS, CuCl, and NH4Br in reducing atmosphere provides the diffusion and volume distribution of Cu+ and Br ions in the two-phase ZnS matrix.

It was stated experimentally in five series of the synthesised phosphors that ZnS:Cu,Br forms the combined sphalerite–wurtzite crystal structure, and the intensity of radioluminescence given by the Cu’Zn-BrS● associates sharply increases at a certain content of the wurtzite phase in ZnS structure 1.

A description of this phenomenon can be provided by the percolation theory instruments. The formation of the long interphase boundary between sphalerite and wurtzite phases in the phosphor grain of ZnS matrix as a percolation infinite cluster analogue results in the grain boundary diffusion rate increasing and an improvement in the luminescence centres’ forming ability on the intercrystalline borders. Associated defects migrating through the volume of the crystal to its surface provide the surface luminescence centres and improve tritium radioluminescence.

Computer modelling of the diffusion process in the discussed system was conducted, and a descriptive model of structure defect migration through the two-phase phosphor structure was developed. The application of this approach in solid-state physical chemistry provides an additional tool for controlling the structure and properties of functional materials.

5. Organic Crystalline Materials

5.1. Exploring the Impact of Edge and Surface Sites on Functionalized Graphene-Based Membrane in H₂S Adsorption: A Computational Study

Janet Eleojo Al-Hassan, Toyese Oyegoke and Olusola Ibraheem AYENI

¹ 

CAD-Engineering of Processes and Reactive Materials Group, Chemical Engineering Department, Ahmadu Bello University, Zaria, Nigeria.

² 

Green Science Forum—Modeling & Simulation, Pencil Team, ABU Zaria, Nigeria

In our modern world, environmental concerns have become paramount, with a particular focus on mitigating the release of harmful gases into the atmosphere. One such gas of significant concern is hydrogen sulphide (H₂S), known for its noxious odour and detrimental effects on both human health and the environment. This study delves into the crucial importance of removing H₂S from effluent gases before their release into the environment. We bridge existing knowledge gaps by investigating the adsorption of hydrogen sulphide on graphene sheets, utilizing advanced computational tools. Through detailed simulations, we explore various adsorption sites on the graphene surface, including top (T), bridge (B), and hollow (H) sites, to determine the most effective removal mechanisms. Most importantly, we carefully explore the impact of the adsorption sites present at the edge and centre regions of the graphene surface. Our study reveals that there are significant differences in the adsorption strength of hydrogen sulphide across the sites present at the edge and surface regions of the graphene sheets, confirming that edge sites are more effective for hydrogen sulphide adsorption. The findings derived from our study not only contribute to a deeper understanding of hydrogen sulphide adsorption but also highlight the promising role of carboxylate-function-decorated graphene (via its edge and surface sites and functional group assessment) in environmentally friendly gas removal technologies.

5.2. Organic Menthol Crystals: An Overview of Innovation Based on Relevant Patents

Reda El Boukhari and Ahmed Fatimi

• Chemical Science and Engineering Research Team (ERSIC), Department of Chemistry, Polydisciplinary Faculty of Beni Mellal (FPBM), Sultan Moulay Slimane University (USMS), P.O. Box 592 Mghila, Beni Mellal 23000, Morocco

Organic menthol crystals, derived from mint essential oils, are natural, waxy, clear, or white crystalline substances that are solid at room temperature, melting slightly above. Menthol, a cyclic monoterpene alcohol, is synthesised from natural or synthetic precursors and has a significant demand globally, with various protocols available for its synthesis. It is commonly used in perfumery, cosmetics, and medicinal products for its cooling effect and minty scent. Menthol’s safety profile and anticancer properties have been extensively studied, showing promising results in inhibiting different cancer cells through multiple pathways like apoptosis induction, cell cycle arrest, and the disruption of tubulin polymerization. Additionally, menthol’s impact on respiratory health and digestive issues and its potential to exacerbate allergic rhinitis have been explored, highlighting both its beneficial and potentially harmful effects on human health [41,42].

In this study, we provide an in-depth overview of innovation based on relevant patents related to menthol crystals and its derivatives and their applications. By analysing these patents, we aim to present the current state of the art and identify emerging trends in the field of plant-derived menthol.

5.3. New Quantitative Visible (VIS) Spectrophotometric Analysis of Pure Oxacillin in a Pharmaceutical: A Statistical Study of Linear Regression

Cristian-Catalin Gavat

• GRIGORE T. POPA University of Medicine and Pharmacy, Faculty of Medical Bioengineering, Biomedical Sciences Department, 16 Universitatii Street, Iasi 700115, Romania (RO)

Oxacillin is a penicillinase-resistant, narrow-spectrum beta-lactam crystalline antibiotic of the penicillin class which is resistant to beta-lactamases. The main purpose of this paper was to develop and apply a new spectrophotometric method in the visible (VIS) field for the analysis of pure Oxacillin from various pharmaceutical samples. Oxacillin reacted completely with 1.10 Phenanthroline 0.2% alcoholic solution in the presence of an aqueous solution of ferric chloride (FeCl₃, 6%), which led to the quantitative formation of an intense bright yellow complex with a faint orange tint, after heating the solutions for 20 min at 70 °C constant temperature. The intense bright-yellow-coloured synthetized complex was then spectrophotometrically determined at λ = 420 nm, corresponding to its absorption maximum, in relation to double-distilled water as a blank. One solid pharmaceutical capsule officially contained 500 mg pure Oxacillin as a reference value. As a result of the experiment, 491.308 mg of pure Oxacillin/solid capsule was obtained. This amount corresponded to a percentage content of 98.262% determined by pure sodium Oxacillin and calculated per solid capsule of pharmaceutical product. The obtained result was very close to the reference value which was 500 mg of pure Oxacillin. The relative percentage deviation (relative percentage procedural error) was only E = 1.738% to the official value, and it fit perfectly within the official normal limits of values indicated by the Romanian Pharmacopoeia, 10th Edition, and by the European Pharmacopoeia Rules (±5%). Statistical analysis revealed a very good linearity of the visible spectrophotometric method for pure standard analysed solutions in a large concentration range, from 1.20 μg/mL to 36.00 μg/mL. The linear regression coefficient R² was 0.999504, and the correlation coefficient R was 0.999752; as R² ≥ 0.9990 and R > 0.9990, they were found to be within the normal official range of values.

5.4. Biological Activities Investigations of New Sulfanilamide Derivative: Single Crystal X-Ray Diffraction Analysis, In Silico ADME, and Molecular Docking Studies

Ines Benzitouni ¹, Nesrine Benarous ², Nabila Moussa Slimane ¹, Hassiba Bougueria ^1,3, Mehdi Boutebdja ^1,4

¹ 

Unité de Recherche de Chimie de l’Environnement et Moléculaire Structurale (CHEMS), Université Frères Mentouri Constantine 1, Constantine, 25017, Algeria

² 

Unité de Recherche de Chimie de l’Environnement et Moléculaire Structurale (CHEMS), Université Frères Mentouri Constantine 1, Constantine, 25017, Algeria

³ 

Centre Universitaire Abd El Hafid Boussouf, Mila, 43000 Mila, Algeria

⁴ 

Laboratoire de Technologie des Matériaux Avancés, Ecole Nationale Polytechnique de Constantine, Nouvelle Ville Universitaire, Ali Mendjeli, Constantine 25000, Algeria

Introduction: Sulphanilamides were the first chemical drugs used as preventive and therapeutic agents against various infection diseases. They generally act as structural analogues of para-aminobenzoic acid and therefore inhibit dihydropteroate synthase. After the discovery of Penicillin, their use decreased significantly. Nevertheless, in recent years, their synergistic activity has gradually attracted the attention of researchers. In this work, we report synthesis, crystal structure, ADME prediction, molecular docking, antibacterial, and toxic activities of new sulphanilamide-derived Schiff base (SB), i.e., 2-(2-hydroxyphenyl)quinoline-6-sulfonamide (HPQS).

Experimental: HPQS is synthesised through a two-step process, viz, reflux and solvothermal methods. In the first step, condensation reactions similar to those reported for similar SB were carried out. The second step involved using a Teflon-lined autoclave. GOLD software was used to conduct docking investigations. ADME parameters and drug-likeness were estimated using SwissADME.

Results and Discussion: Single-crystal X-ray diffraction indicates that the HPQS crystallize in P2₁/c space group, with two molecules in the asymmetric unit (A and B). The crystal structure features N—H⋯O, C—H⋯O, and C—H⋯π hydrogen bonds and π–π stacking interactions. Additionally, drug-likeness and pharmacokinetics parameters revealed that the compound exhibited favourable ADME properties. Finally, molecular docking study was carried out to investigate the possible binding mode of the sulphanilamide derivative. Molecular docking studies and biological screening of HPQS explored its diverse potential application as antibiotic agent. It showed high negative binding scores due to the presence of different hydrogen-bonding types. Therefore, docking studies revealed strong interactions and high binding potencies and affinities against the tested macromolecular receptors.

Conclusions: In this study, we have reported the synthesis and characterisation of new SB derived from sulphanilamide (HPQS). Considering the findings of the study, it has been proven that this new compound constitutes a promising therapeutic agent capable of managing bacterial infections.

5.5. Synthesis and Crystal Structure Analysis of Monochloroacetic Acid 2,4-Dinitrophenylhydrazide

Ruzimurod Sattorovich Jurayev ¹, Azimjon Uralivich Choriyev ²and Machram Gasanovich Abdullayev ³

¹ 

Department of “Chemical Engineering and Quality Management”, Shakhrisabz Branch of Tashkent Institute of Chemical Technology, 20, Shahrisabz str., Shakhrisabz, Uzbekistan, 181306

² 

Karshi State University, Kuchabog street, 17, 180103, Karshi, Uzbekistan

³ 

Department of “Physical and organic chemistry”, Dagestan State University, 43a, Gadjiyeva str., Makhachkala 367001, Russia

Our main goal was to form various compounds of the chloroacetylation product of p-methoxyphenol (4-methoxyphenyl 2-chloroacetate) with various amines using a Menshutkin reaction. This article presents a part of our research, namely the reaction process with 2,4-dinitrophenyl hydrazine and its analysis. The process was carried out in different solvents. The expected product of the reaction was 2-(2,4-dinitrophenyl)-1-(2-(4-methoxyphenoxy)-2-oxoethyl)hydrazin-1-ium chloride. Due to regrouping, another product was formed. As a result of our research, 2,4-dinitrophenylhydrazide of monochloroacetic acid (2-chloro-N′-(2,4-dinitrophenyl)acetohydrazide) was formed. Crystal structure analysis was performed. This is of interest because of its potential applications in various fields, including pharmaceuticals and materials science. The synthesis of the compound was achieved by a direct synthetic route and confirmed by spectroscopic methods such as IR, NMR, and elemental analysis. Single-crystal X-ray diffraction analysis provided detailed structural information, revealing the molecular arrangement within the crystal lattice. Crystallographic data revealed a monoclinic crystal system with the space group P21/n, which revealed the molecular conformation, intermolecular interactions, and crystal packing motifs. This comprehensive structural characterization enhances our understanding of the compound’s properties and provides valuable insights for further exploration of its potential applications. As a result, a compound with a confirmed crystal structure was entered into the reference of Structures The Cambridge Crystallographic Data Centre (CCDC).

5.6. Synthesis, Crystal Structure, and Hirshfeld Surface Analysis of Isomeric ((1-(4-nitrophenyl)-1H-1,2,3-triazol-4(5)-yl)methoxy)benzaldehyde Compounds

Muminjon Hakimov ¹, Ilkhomjon Ortikov ², Ibragimdjan Abdugafurov ³, Burkhon Elmuradov ², Halima Mouhib ⁴ and Akmaljon Tojiboev ⁵

¹ 

Namangan State University, Bobur Shoh str. 161, Namangan, 160107, Uzbekistan

² 

Institute of the Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Mirzo Ulugbek Str. 77, Tashkent 100170, Uzbekistan

³ 

National University of Uzbekistan, University Str., 4, Tashkent 100174, Uzbekistan

⁴ 

VU Bioinformatics, Computer Science Department, Vrije Universiteit Amsterdam, De Boelelaan 1111, 1081 HV Amsterdam, The Netherlands

⁵ 

University of Geological Sciences, Olimlar Str. 64, Tashkent 100170, Uzbekistan

Among nitrogen-containing heterocyclic compounds, triazoles have high pharmacological properties and are therefore of interest for structural and physico-chemical studies. Structurally, triazoles can be divided into two different subsets: 1,2,3-triazole and 1,2,4-triazole. Due to their structural characteristics, 1,2,3- and 1,2,4-triazoles can accommodate a wide range of substituents (electrophiles and nucleophiles) around their core structures, opening the way for the synthesis of various new bioactive substances. Although it has been more than 120 years since the initial discovery of the method for the synthesis of 1,2,3-triazoles by cross-alkynes and azides, the interest in this chemical class of molecules has been increasing rapidly in the last 20 years. The reason for this is the introduction of catalytic methods for cyclization reactions, which made the generation of 1,2,3-triazole derivatives widely accessible for pharmacological applications. With the advancement of click chemistry, scientific work on these five-member heterocyclic compounds is growing rapidly. Here, we report the synthesis and structural characterization of 2-((1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)methoxy)benzaldehyde (1) and 3-((1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)methoxy)benzaldehyde (2) using X-ray crystallography. The structures of compounds 1 and 2 were established by single-crystal X-ray diffraction, and the identified conformations were described in the context of their stabilizing intra- and inter-molecular interactions, particularly highlighting the significant hydrogen bonds of the crystals. For molecular crystals, Hirshfeld surface analyses can provide crucial insight into the intermolecular interactions. These analyses were performed to determine intermolecular interactions in 1 and 2. According to our results, the molecules are associated by intra- and intermolecular hydrogen bonds, C—H···π, and N—O···π stacking interactions. The three-dimensional Hirshfeld surface analysis and two-dimensional fingerprint plots revealed that the structures are dominated by H···H, H···C/C···H and H···O/O···H contacts.

5.7. Arrays of Lander Molecules Stabilized by Multiple Interactions on Surfaces

Nadia El Hasnaoui and Youness Benjalal

• Université Sultan Moulay Slimane, Faculté polydisciplinaire, Département de chimie, ERSIC, Béni Mellal, Morocco

Molecular assemblies driven by non-covalent interactions have sparked enormous interest in the last decade, due to their high versatility, flexibility, and recoverability. To figure out the interplay of the non-covalent interactions, such as hydrogen bonding (HB), electrostatic interaction, stacking, metal–organic coordination, van der Waals (vdW) forces, etc., intensive attention has been focused on the sophisticated systems composed of multiple components that are balanced by multiple non-covalent interactions.

Theoretical investigations have been carried out with an extended semiempirical atom superposition and electron delocalization (ASED+, Atom Superposition, and Electron Delocalization), based on the extended Hückel molecular orbital theory. Calculated STM images were obtained within the EHMO-ESQC method (Extended Hückel Molecular Orbital–Elastic-Scattering Quantum Chemistry), which describes the electronic scattering between the substrate and the tip by modelling the chemical structure of the tunnel gap (substrate, molecule, tip apex, and tip substrate).

Molecular Landers are a distinctive family of molecules, with bulky functional groups acting as the legs to lift up the aromatic molecular board. When the compounds are adsorbed on surfaces, only the legs are in contact with the surface, while the molecular board is decoupled from the substrate. To align these Landers into extended and well-ordered arrangements, different routes have been employed. In our previous work, we have demonstrated that one-dimensional (1D) and two-dimensional (2D) well-ordered assemblies of Landers can be observed not only between the same compounds but also between hetero-Landers. However, all these interactions occurred when the molecular boards have an identical or comparable height, while the possibility of bonding between Landers and legless molecules remains unknown. Moreover, besides the two routes mentioned above, guest–host chemistry has been recognized as another fascinating way to align molecules on surfaces.

5.8. Investigating the Crystallization Process of Medical Bio-Polymer Poly(3-hydroxybutyrate) Using Experimental Methods and Coarse-Grained Molecular Dynamics Simulations

Muhammad Asif Hossain and Anton Pavlovich Bonartsev

• Faculty of Biology, Moscow State University

Poly(3-hydroxybutyrate) (PHB) is a storage compound synthesised by the bacteria Azotobacter chroococcum. This semi-crystalline polymer is both biodegradable and biocompatible, making it an ideal compound for tissue engineering materials. The key determining factor of the physical and mechanical properties of materials based on PHB is the distribution of amorphous and crystalline phases. Our research aims to further the understanding of how these phases arise and how they interact with each other. Five PHB samples with molecular masses ranging from 384 kdA to 1095 kdA were used for the current study. Raman spectroscopy and surface-free energy calculations were carried out. From our experiments, it was found that samples had similar surface-free energies. Three different boxes of molecular dynamics simulations representing three different hypotheses were set up: a box according to a classical theory of nucleation, a box with shear flow, and a box with heightened hydrophobic interactions. Our simulations show that a box according to the classical theory of nucleation shows the smallest amount of self-organization, while the heightened hydrophobic interactions give rise to configurations that resemble reality the most. From our results, we can conclude that for semi-crystalline biological polymers such as PHB, hydrophobic interactions play a significant role in self-organization during the crystallization process.

5.9. Nucleation, Nuclei Stability, and Crystal Growth in Supercooled Organic Melts of Benzocaine and Tolbutamide

Timur A. Mukhametzyanov ¹, Ruslan A. Andrianov ¹ and Christoph Schick ²

¹ 

Department of Physical Chemistry, Kazan Federal University, Kremlevskaya str. 18, 420008 Kazan, Russia

² 

Institute of Physics & Competence Centre CALOR, University of Rostock, Albert-Einstein-Str. 23-24, 18051 Rostock, Germany

The investigation of crystallization kinetics in supercooled melts has spanned more than a hundred years and is relevant to many areas of science and technology. Conventional techniques, however, limit the range of systems where this study is possible due to relatively slow crystallizers. As such, the nucleation kinetics in supercooled melt was accessed only for a few organic compounds.

Fast scanning calorimetry (FSC) allows us to greatly increase the range of molecules that can be supercooled by providing a cooling rate of thousands of degrees per second and beyond. FSC was extensively used to study nucleation and crystallization kinetics in polymers, but rather few applications of the method to small organic molecules are reported. Using the FSC technique, we have studied the nucleation and crystallization of benzocaine, a rapidly crystallizing molecule, from supercooled melt. The nucleation of benzocaine was observed at –70 °C (supercooling of about 160 degrees), which is more than 50 degrees below the glass transition of the compound. The crystallization half-times greatly depend on temperature and cover nearly five orders of magnitude.

Nucleation and crystal growth in the supercooled melt were also studied in tolbutamide. Compared to benzocaine, tolbutamide has lower critical cooling and heating rates, permitting the application of the two-stage nuclei development method based on FSC. In tolbutamide, the isothermal nucleation and crystallization kinetics were studied. A modified two-stage nuclei development technique was used to probe the nuclei stability and obtain an estimate of the lateral growth rate of the nuclei, providing a unique insight into the properties of crystal nuclei. The interplay between the nucleation, crystallization, and polymorphism of tolbutamide was also accessed.

The results of the measurements are discussed in the framework of the Classical Nucleation Theory.

6. Hybrid and Composite Crystalline Materials

6.1. Elucidating the Role of the O-Methoxy Group at the Lower Rim-Appended Salicylideneamine Substituents of Calix[4]Arene Ligands on the Molecular and Electronic Structure of Dinuclear Fe(III)-Based “Diamond Core” Complexes

Angelina Iova ¹, Iuliia Strelnikova ^1,2, Alexander Ovsyannikov ², Igor Litvinov ², Andrew Pyataev ¹, Islamov Daut ¹, Svetlana Solovieva ^1,2, Igor Antipin ^1,2

¹ 

Kazan Federal University, Kazan, Russian Federation

² 

Arbuzov Institute of Organic and Physical Chemistry, FRC KSC, RAS, Kazan, Russian Federation

New materials capable of storing and processing information at the level of a single molecule (atom) will contribute to the development of digital technologies. This type of molecules has to possess the property of bistability—the ability of molecules to exist in two stable spin states, for example, spin-crossover. In recent decades, there has been a growing interest in control over spin states of coordinative compounds based on Fe(III) cations because of their potential application in fields like molecular spintronics, memory and electronic devices, switches, and sensors [43].

The rational design of molecular building blocks allows researchers to manage the coordination sphere of the metal, and hence magnetic properties can be controlled [44]. Due to the possibility of wide functionalization, calix[4]arenes are extremely attractive for the design of pre-organized ligands. Moreover, the modification of calix[4]arene makes it possible to tune the structure of the complexes as well as to control their size and geometry. Disubstituted derivatives of calix[4]arenes allow for the fine-tuning of the metal environment by varying the length of the alkyl spacer and the nature of the substituent in the coordinating fragment. It is particularly attractive to obtain salen-type ligands possessing N,O-coordinating chelate fragments.

In this work, we report on the synthesis of new Fe(III)-complexes based on polydentate lower rim disubstituted calix[4]arenes ligands, displaying a salen-type coordination pocket. The structures of prepared coordination compounds were studied by means of X-ray diffraction analysis, IR and 57Fe Mössbauer spectroscopy, and HR-ESI mass spectrometry. The structure–property correlation is also discussed.

6.2. TiO₂ Nanotubes Decorated with Ag Spheres for Electrochemical Sensing Applications

Alba Arenas-Hernandez ¹ and Mario Moreno ²

¹ 

Institute of Physics, Autonomous University of Puebla

² 

Instituto Nacional de Astrofísica, Óptica y Electronical

The detection of organic and inorganic compounds using electrochemical sensors has garnered attention due to their low-cost fabrication and excellent sensitivity. To enhance the sensitivity of the sensor using metal oxides as active materials, defect states such as oxygen vacancies have been studied. These defects operate as donor levels near the conduction band of the metal oxide. In this study, we present the synthesis of TiO₂ nanotubes decorated with Ag spheres, along with an investigation into their chemical, structural, and optical properties for electrochemical sensing applications. TiO₂ nanotubes were synthesised through a three-step anodization process, while Ag spheres were deposited using electrochemical deposition. The electrolyte solution for the growth of TiO₂ nanotubes consisted of ammonium fluoride and ethylene glycol, while silver nitrate and citric acid were employed as the electrolyte solution for Ag sphere deposition. FE-SEM analysis revealed the successful deposition of Ag spheres with a spherical morphology over TiO₂ nanotubes, with the morphology being significantly influenced by the concentration of organic acid in the electrolyte solution. Stoichiometry analysis was performed on both the TiO₂ nanotube film and on the film decorated with Ag spheres. Additionally, the band gap energy was calculated from the diffuse reflectance spectroscopy (DRS) spectrum. According to photoluminescence analysis, a larger area associated with oxygen vacancies in TiO₂ nanotubes decorated with Ag spheres was identified. The presence of localized energy levels within the band gap resulting from oxygen vacancies and Ag spheres led to a reduction in the band gap energy of the semiconductor. This phenomenon is particularly relevant for creating more active sites suitable for the adsorption of compounds in electrochemical sensing applications [45,46].

6.3. Separation of Benzene and Cyclohexane on a Metal–Organic Framework with an Alicyclic Ligand

Anna Ovchinnikova ^1,2 and Pavel Demakov ³

¹ 

Novosibirsk State University, department of natural sciences, 630090, Novosibirsk-90, 2 Pirogova Str

² 

Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences NIIC SB RAS 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia

³ 

Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, NIIC SB RAS 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia

In industry, cyclohexane is obtained exclusively through the hydrogenation of benzene, but the subsequent complete separation of these liquids is very difficult, since they have similar boiling points and form an azeotrope. Their selective adsorptive separation using metal–organic frameworks (MOFs) is one of the promising approaches. Two- and three-dimensional MOFs contain cavities, the size, geometry, and chemical nature of which enable the isolation of the desired component from a difficult-to-separate mixture. Combining various organic ligands and metal ions provides almost unlimited design possibilities for MOFs.

The present study considers the sorption of benzene and cyclohexane for five previously reported MOFs based on trans-1,4-cyclohexanedicarboxylic acid acting as an example of a ligand with a saturated carbon skeleton: [Ga(OH)(C₈H₁₀O₄)] (1), [Ca(H₂O)₂(C₈H₁₀O₄)]·H₂O (2), [Zr₆O₄(OH)₄(C₈H₁₀O₄)₆] (3) [47], [Cu₂(C₈H₁₀O₄)₂] (4) [48], [Al(OH)(C₈H₁₀O₄)]·H₂O (5). The adsorption of individual compounds from the liquid and gas phase and competitive adsorption from mixtures were investigated.

For MOFs 3 and 4, the high selectivity of benzene sorption over cyclohexane was determined, with volume-by-volume selectivity up to ~13. Further, benzene/cyclohexane adsorption selectivities were calculated from the adsorption data using two methods. According to the Henry method, the C₆H₆/C₆H₁₂ Henry constant ratios at low pressures were 7105 for [Zr₆O₄(OH)₄(chdc)₆] and 3.63 for [Cu₂(chdc)₂]. According to the ideal adsorbed solution theory (IAST) for near-atmosphere pressures, the corresponding selectivity coefficients were 23.6 for [Zr₆O₄(OH)₄(chdc)₆] and 1.23 for [Cu₂(chdc)₂].

These results indicate the promising potential of using metal–organic frameworks 3 and 4 with an alicyclic ligand as highly effective sorbents for the separation of the industrial mixtures of benzene and cyclohexane.

6.4. Tailoring Magnetite Nanocrystal Morphology via Solvothermal Method for Enhanced Heavy Metal and Fluoride Adsorption

Diego-Antonio Corona-Martinez ¹, Prócoro Gamero-Melo ², Lourdes Díaz-Jiménez ³, Alejandro Zermeño-González ⁴, Audberto Reyes-Rosas ⁵ and Sasirot Khamkure ⁶

¹ 

Soil Science Department, Universidad Autónoma Agraria Antonio Narro, Saltillo, 25315 Coahuila, Mexico

² 

Sustainability of Natural Resources and Energy, CINVESTAV Saltillo

³ 

Sustainability of Natural Resources and Energy, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Saltillo, 25900 Coahuila, Mexico

⁴ 

Irrigation and Drainage Department, Universidad Autónoma Agraria Antonio Narro, Saltillo, 25315 Coahuila, Mexico

⁵ 

Department of Bioscience and Agrotechnology, Research Center of Applied Chemistry

⁶ 

CONAHCYT-Universidad Autónoma Agraria Antonio Narro, Mexico

Contamination by heavy metals is a pressing issue due to its numerous hazardous effects on human health. One of the main challenges associated with this type of contamination is the resistance of heavy metals to degradation and their accumulation in living organisms. However, a wide variety of methods, including ion exchange, membrane filtration, flotation, electrolytic methods, and adsorption, can be employed to eliminate heavy metals from water. To achieve the efficient removal of heavy metals from water, a high-surface-area absorbent is necessary. This enhances contact and interaction with heavy metal ions, and the use of nanoparticles significantly improves this aspect. This study investigates the preparation of Fe₃O₄ nanoparticles using a solvothermal method. This method allows us to produce ultrafine magnetite powders with homogeneous particles, a narrow size distribution, and consistent morphology, free from other crystalline phases that could hinder heavy metal ion absorption. The experiments involved varying temperatures (180–220 °C) and reaction times (4–12 h) and utilized FeCl₃ as the iron ion precursor. Following the solvothermal treatments, the precipitated particles were magnetically separated from the hydrothermal solution. The magnetic particles were then analysed using XRD, SEM, and FTIR. Structural characterization via SEM confirmed that the obtained particles were magnetite in the form of homogeneous spherical particles with an average size of 450 nm, composed of smaller agglomerated nanoparticles with an average size of 8.4 nm. Microstructural characterization using the XRD and FTIR techniques also confirmed the magnetite structure, exhibiting defined reflections without any secondary crystalline phases. Kinetic and isotherm data from a preliminary study fit well with established models, indicating efficient fluoride capture. Additionally, the maximum adsorption capacity reached 39.44 mg/g F⁻ within 30 min, remaining stable thereafter. These findings suggest that the synthesised magnetite nanoparticles are ideal candidates for heavy metal and fluoride removal from water.

6.5. Photoluminescence Behavior Combined with Multiple Electrical and Optical Properties in Organic-Inorganic Hybrid Manganese (II) Halide Perovskite

Dinesh Kulhary

• Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi 110067, India

Organic–inorganic hybrid materials have emerged as a potential candidate due to their fascinating properties for several optoelectronic applications. In this study, lead-free organic–inorganic hybrid perovskite single crystals [N(CH₃)₄]MnCl₃ were synthesised through a slow evaporation method using tetramethylammonium as the organic ligand. Systematic characterizations were carried out to reveal the crystal structure and other optoelectrical properties. A series of systematic characterizations were carried out in order to reveal the crystal structure as well as other optoelectrical features. Phase purity and morphology were confirmed using powder X-ray diffraction and scanning electron microscopy, respectively. The crystal has a P 63/m space group which belongs to the hexagonal crystal system. The optical band gap was found to be 2.15 eV, and under the excitation of a suitable UV light source, it can emit 635 nm bright red lights with a full width at half maximum of 78 nm at room temperature. Thermal study indicates that the compound is stable up to 300 °C. The compound’s electrical properties were studied using impedance spectroscopy as a function of frequency from 20 Hz to 4 MHz at different temperatures. Finally, the successful achievement of luminescent printing was made possible by harnessing the exceptional photophysical properties of the material. The printed images demonstrated remarkable clarity even after undergoing multiple cycles and remained visible for a prolonged period of 15 days in an air environment, affirming the stability of the printed images. The information stored on the paper can be easily read using a UV lamp. Therefore, these findings highlight the material’s outstanding photoluminescence and optoelectrical properties, suggesting its potential for promising applications in optoelectronics, including light-emitting diodes.

6.6. Phase Behavior of Athermal Colloidal Mixtures of Chains and Monomers

Olia Bouzid, Daniel Martínez-Fernández, Miguel Herranz and Nikos Ch. Karayiannis

• Universidad politécnica de Madrid

Through extensive Monte Carlo simulations, we study the phase behaviour of systems composed of freely jointed, hard-sphere polymers and monomers at different number fractions. This work is inspired by the fact that, despite their similarities in crystallization, the melting point of hard-sphere chains [49] is higher than that of their monomeric counterparts [50].

System configurations are generated, equilibrated, and successively analysed through the Simu-D software [9]. The equilibration part is primarily based on chain-connectivity-altering [51] and identity-exchange Monte Carlo algorithms, especially designed for mixtures of chains and monomers of the same chemical constitution. The structural identification of the computer-generated system configurations is performed through the characteristic crystallographic element (CCE) norm descriptor [10].

We systematically study how both the packing density and the relative number fraction affect the ability of the systems to crystallize. We further identify the entropic origins of the phase transition and the difference in the local environment between spheres belonging to chains and individual ones. Depending on the simulation conditions, different morphologies are established ranging from predominantly amorphous packings to crystal morphologies of mixed hexagonal close-packed (HCP) and face-centred cubic (FCC) character. Extensions of the present work include the molecular simulation of athermal mixtures based on semi-flexible polymers.

6.7. Study of Structure and Filler Crystallinity Index of Polymer Composite with Silica Nanofibrous Filler

Natalia Igorevna Cherkashina, Vyacheslav Ivanovich Pavlenko, Semen Nikolayevich Domarev and Dar’ya Aleksandrovna Ryzhikh

• Department of Theoretical and Applied Chemistry, Belgorod State Technological University Named after V.G. Shukhov, 308012 Belgorod, Russia

Introduction: In this study, the technique of obtaining a composite material based on polyimide track membranes prepared by the deposition of TEOS (tetraethoxysilane) hydrolysis products in a medium with acidic catalyst will be considered further. The obtained material sample microstructure and effect of the presence of crystalline forms of silicon dioxide on the overall crystallinity index (CI) of the silica filler will be studied.

Methods: The microstructure of the composite material surface was studied using scanning electron microscopy (SEM TESCAN MIRA 3). The effect of the presence of crystalline forms of silicon dioxide on the overall CI of the silica filler was studied using XRD (ARL X’TRA). For the purpose of this study, the CI was defined as the ratio of the area of the peaks of the crystalline phase in the diffraction pattern to the total area under it. A series of experiments were carried out with model samples with different wt.% contents of crystalline silica powder and a correlation curve of the crystallinity of the sample, and the crystallinity from the diffraction pattern was plotted.

Results: From the surface examination of the samples, it was found that the silica filler deposited in the pores of the polyimide track membrane has a nanofibrous structure. When crystalline powders were added in the amount of 30% wt. of the planned reaction yield, the CI did not exceed ≈ 32%, which indicates the absence of the formation of a new crystalline phase in the reaction volume.

Conclusion: According to the study conducted on the advantages of using an acidic catalyst of TEOS, the hydrolysis reaction can be regarded as the most successful, since its use leads to the formation of nanofibrous structures in the pores of the polyimide track membrane. The addition of crystalline forms of silicon oxide studied in this paper did not result in a significant change in the CI of silica filler.

6.8. New Antimicrobial Systems Based on Zeolites with RE = La, Gd Functional Ions

Elena N. Domoroshchina ¹, Daria A Tarkhanova ¹, Galina M Kuz’micheva ¹ and Raisa P Terekhova ²

¹ 

MIREA—Russian Technological University

² 

Vishnevsky Institute of Surgery

Antibiotic resistance necessitates the transition to fundamentally new drugs, in particular RE(NO₃)₃ × xH₂O salts [52]. To reduce the active substance (RE ion) content in drugs while maintaining their functionality, RE/MFI and RE/BEA systems based on MFI and BEA zeolites are offered.

Composites with MFI ((H_x)[(Fe³⁺_xSi⁴⁺_12-x)O₂₄] with Si/Fe = 25.68: MFI(Fe25), MFI(Fe68); [(Ti⁴⁺_xSi⁴⁺_12−x)O₂₄] with Si/Ti = 47.60: MFI(Ti47), (MFI(Ti60)); and BEA ((H_x)[(Al³⁺_xSi⁴⁺_12−x)O₂₄] with Si/Al = 12.150: BEA(Al12), BEA(Al150)), and RE(NO₃)₃ × 6H₂O (RE = La, Gd) salts were obtained using the cold impregnation method, with solid-phase mixing of the components (1:1.2), grinding (~4 min), and annealing (250 °C, 1 h).

The compositions of RE/BEA include amorphous components. Moreover, the samples differ in their particle/associate sizes (N, µm), which are greater with MFI (N = 12.5–35 µm) than with BEA (N = 7.5–8 µm), except for RE/MFI(Ti60).

The growth inhibition zones (D,mm) of the bacteria S. aureus, E. coli, P. aeruginosa, A. baumannii, and K. Pneumonia and the fungi C. albicans, C. glabrata, and C. parapsilosis on the salts change from D = 28 to D = 50 mm with D_max for S. aureus on Gd; from D = 45 to D = 56 mm with D_max for C. albicans on La, which is a record for these microorganisms; and D = 0 mm for zeolites. The microorganisms showed high sensitivity to the composites—A. baumannii and P. aeruginosa with D_max = 38 mm on Gd/MFI(Ti60) and Gd/MFI(Fe68); and C. parapsilosis with D_max = 45 mm on Gd/MFI(Fe68)—but less compared to that seen for the salts while maintaining their excellent biocidal properties. All the new systems demonstrated antimicrobial activity higher than that of the antibiotic penicillin, which makes them promising for biomedical purposes.

Funding: Funding was received from the Ministry of Science and Higher Education of the Russian Federation, grant number FSFZ-2024-0003.

6.9. Extraction and Modification of Cellulose Nanocrystals

Nadia Anter ¹, Mohamed Yassine Guida ¹, Ahlam Chennani ², Abdelouahid Medaghri-Alaoui ¹ and Abdellah Hannioui ¹

¹ 

Molecular Chemistry, Materials and Catalysis Laboratory, Faculty of Sciences and Techniques (FST-BM), University of Sultan Moulay Slimane (USMS), 23000, Béni-Mellal, Morocco

² 

Molecular Chemistry, Materials and Catalysis Laboratory, Faculty of Sciences and Techniques, University of Sultan Moulay Slimane (USMS), 23000, Béni-Mellal, Morocco

Depending on the source, cellulose microfibrils produced during biosynthesis can range in size from 2 to 20 nanometres in diameter and up to several micrometres in length. Crystalline domains are scattered throughout each microfibril, which also contains amorphous and disordered regions. Chemical hydrolysis is used to break down amorphous chains and liberate crystalline domains from cellulose fibres in order to create cellulose nanocrystals. Sulfuric acid hydrolysis has been used more frequently for the synthesis of cellulose nanocrystals (CNCs) due to its excellent efficiency, as reported in the majority of studies. When sulfuric acid is used as the hydrolysing agent, disordered or paracrystalline portions of cellulose fibres are preferentially hydrolysed, while crystalline parts with a higher resistance to acid attack are left intact. It should be noted that sulphuric acid can react with the hydroxyl groups of cellulose during hydrolysis, producing charged sulphate esters on the surface of nanocrystals and facilitating the dispersion of nanoparticles in water. The modification of CNCs is intended to lower the surface energy and increase the degree of dispersion by converting the polar hydroxyl groups on the surface of nanocrystals into moieties that can improve the interactions with non-polar polymers. The main challenge in the surface modification of CNCs is to select a reagent and reaction medium that will allow for modification in a way that preserves the original morphology of the nanocrystals while only changing the surface. The synthesis of glycosilicones from cellulose nanocrystals generally involves several reaction steps: catalysts capable of catalysing the allylation reaction of cellulose combine cellulose with allyl bromide, followed by a hydrosilylation reaction, are then catalysed by Karstedt based on platine (0) to combine the hydrophilic allylated cellulose and hydride-terminated hydrophobic silicone. The final polymers were characterized by FTIR, 1H NMR, and solid-state SEM. The glycosilicones were insoluble in water but swelled in organic solvents.

7. Materials for Energy Applications

7.1. Using Cutting-Edge Architectural Technologies and Creative Materials to Support Smart Building Design Paradigm

Amit Kumar Jaglan

• School of Planning and Architecture, New Delhi, India

Because of its benefits and digitization, smart materials technologies are becoming increasingly popular worldwide, and smart building construction is becoming a new development trend. These technologies are essential for achieving a competitive edge in the construction sector in the twenty-first century. It is anticipated that smart materials will dramatically improve functionality in the development of materials technology by acting like living systems and becoming a component of a structural system that is sensing its surroundings. This study examines the advantages of implementing smart materials technology in the building sector, even if there is less interest in this trend overall, especially in developing nations, than in traditional buildings. This paper also examines the increasingly apparent conventional division between materials science and architecture. It offers a critical examination of smart materials, shedding light on cutting-edge approaches and strategies that will influence architectural design and underscoring the close relationship between the two disciplines. The benefits of smart materials technologies are highlighted in this study, and they include safer, more secure operations, cost-effective maintenance, efficient energy use, employment creation, healthcare management, and real-time monitoring. As such, emerging economies must fully comprehend these advantages. This study emphasizes the advantages of smart materials technology for developing nations and makes the case for the necessity of a collaborative framework between academics and industry professionals in the building industry to advance understanding and successful implementation of this technology.

7.2. Recovery of Precious Metals from the Spent Catalyst

Chaitanya Hirenkumar Jani ¹, Sreekanth Damodaran ², Niraj Nair ³ and Vimal Gandhi ⁴

¹ 

Sixth-semester Bachelor of Engineering student at the Department of Chemical Engineering, Faculty of Technology, Dharmsinh Desai University, Nadiad-387001, Gujarat, India

² 

PhD student at the Department of Chemical Engineering, Faculty of Technology, Dharmsinh Desai University, Nadiad-387001, Gujarat, India

³ 

Assistant Professor at the Department of Chemical Engineering, Faculty of Technology, Dharmsinh Desai University, Nadiad-387001, Gujarat, India

⁴ 

Professor at the Department of Chemical Engineering, Faculty of Technology, Dharmsinh Desai University, Nadiad-387001, Gujarat, India

Catalysts are indispensable in accelerating chemical reactions, and numerous chemical industries rely on heterogeneous catalysts to efficiently transform raw materials into final products. The petroleum, petrochemical, and chemical industries employ a range ofheterogeneous catalysts to optimize the conversion of raw materials into products, achieving this with minimal energy expenditure and reduced processing time. Resource scarcity and disposal issues with low-activity catalysts pose major global challenges. Fresh catalysts incur high costs, and the Earth’s supply of essential metals is limited. Landfilling of spent catalysts, which contain valuable and expensive metals, is harmful to human health and the environment. Recycling catalytic minerals reduces the need for new resources, aiding in resource conservation. Conventional recovery methods employed at the commercial level, namely pyrometallurgy and hydrometallurgy, are effective but exhibit considerable drawbacks, including high energy demands and notable environmental impacts. Despite the availability of numerous environmentally friendly techniques for metal recovery, their implementation remains inconsistent. Organic acids are considered more environmentally friendly and cost-effective compared to inorganic acids for the extraction of precious metals. Crude spent catalysts contain trace amounts of valuable metals, such as 0.21 wt.% platinum and 0.25 wt.% rhenium, and the primary objective is the recovery of these metals using organic acids. A 1 M solution of tartaric acid achieved over 90% platinum extraction from spent catalysts within 24 h at 80 °C. In comparison, organic acid-based hydrometallurgy exhibits significant potential for the recovery of precious metals from spent catalysts.

7.3. Highly Dispersed Ultra-Small NiO Nanoparticles on Mesostructured Silica as Efficient Catalysts for CO₂ Methanation

Fausto Secci, Luciano Atzori, Maria Giorgia Cutrufello, Daniela Meloni, Carla Cannas, Elisabetta Rombi

• Department of Chemical and Geological Sciences, University of Cagliari

Introduction. Due to the attention toward global warming, the current research is focusing on green fuels obtained by the reduction of captured CO₂ (e-fuels). A prominent example of these e-fuels is methane. Ni-based catalysts are among the most investigated systems for CO₂ methanation. Ni is often paired with a promoter, like CeO₂. In this work, composite catalysts consisting of a NiO and NiO/CeO₂ active phase dispersed on mesostructured silica (SBA-15) are presented, which, using a support, should allow us to reach a high activity with a reduced amount of the active phase.

Methods. To obtain NiO- and NiO/CeO₂-based nanocomposites, two different impregnation approaches were used: two-solvent (TS) impregnation and impregnation based on a self-combustion (SC) reaction. The NiO-based catalysts were obtained with a loading of 4.5%; the NiO/CeO₂-based catalysts were obtained using a 1:1 Ni:Ce molar ratio. To determine their structural and morphological properties, the catalysts were characterized with small-angle (SA-) and wide-angle (WA-) XRD (X-ray diffraction), TEM (transmission electron microscopy), and nitrogen physisorption and tested for CO₂ methanation.

Results and discussion. WA-XRD shows that the composites obtained with SC do not feature a diffraction peak, suggesting that NiO and CeO₂ are deposited into the mesopores as ultra-small nanoparticles. On the other hand, the composites obtained with TS impregnation show broad but visible crystal reflections attributed to both NiO and CeO₂, indicating that the active phase has crystallized, forming larger nanoparticles. This finding is also confirmed by the TEM micrographs, which, for the SC composites, do not show the presence of any visible particles outside the mesopores; the TS systems, conversely, show visibly darker nanoparticles dispersed over the support. The catalytic tests show a positive effect of CeO₂ on performance; furthermore, the catalysts obtained with SC impregnation show a higher CO₂ conversion, presumably due to the higher dispersion of the active phase obtained with this approach.

7.4. Magnetocaloric GdMn_1-xRu_xSi Compounds with x = 0 − 1 for Gas Liquefaction

Roman Mukhachev ¹, Sergey Platonov ², Anatoly Kuchin ², Aleksey Volegov ^2,3, Vasilii Gaviko ^2,3, Mari Yakovleva ², Alexey Lukoyanov ^2,3

¹ 

M.N. Mikheev Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences

² 

M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Yekaterinburg, Russia

³ 

Ural Federal University named after the first President of Russia B.N. Yeltsin, 620002 Yekaterinburg, Russia

Ternary intermetallic compounds based on rare-earth metals are characterized by high values of the magnetocaloric effect (MCE) and magnetoresistance, making them suitable materials for a variety of innovative, environmentally friendly and efficient applications. Magnetic refrigeration, for example, is a potential candidate for environmentally friendly gas liquefaction and for preventing gas from evaporating during storage. As an example, liquid nitrogen is often used as a final refrigerant for liquefied natural gas at 111 K. Novel intermetallics GdMn_1−xRu_xSi with a tetragonal CeFeSi-type structure (P4/nmm), were synthesised, with x = 0, 0.2, 0.5, 0.8, and 1 [53]. Their Curie temperature T_C changes from 78.3 to 320 K with a change in manganese content. The electronic structure and magnetic moments of GdMn_1-xRu_xSi intermetallic compounds were calculated using the theoretical DFT+U method. The calculated total magnetic moments of GdMn_1−xRu_xSi also show reduced values for intermediate Ru concentrations. In the GdMn_1−xRu_xSi system, MCE occurs during a second-order phase transition and in a wide temperature range from 78.3 (which is near the boiling point of liquid nitrogen at 77.4 K) to 320 K. The GdMn_1−xRu_xSi system, with x = 0 − 1, is of practical interest for the liquefaction of gases, including nitrogen. A cassette can be made from compounds within this range with slightly varying chemical compositions. Due to their properties, the intermetallic GdMn_1−xRu_xSi compounds are novel, more efficient magnetocaloric materials suitable for the liquefaction of nitrogen and other gases.

7.5. Electronic Structures of Cs₃GdCl₆ and Cs₃NdCl₆ Double Perovskite Crystals Using First-Principles Calculations

Atsushi Suzuki, Takeo Oku

• Department of Materials Chemistry, The University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga 522-8533, Japan

Electronic structures of all inorganic rare-earth element, such as gadolinium (Gd) and neodymium (Nd), double perovskite crystals (Cs₃GdCl₆ and Cs₃NdCl₆) were characterized for application of photovoltaic devices with photovoltaic performance. The band structure, density of state, electron density distribution, and the real and imaginary parts of the dielectric function of Cs₃GdCl₆ and Cs₃NdCl₆ double perovskite crystals were approximated using first-principles calculations, with GGA-PBE approximation. The Cs₃GdCl₆ and Cs₃NdCl₆ double perovskite crystals had a narrow band dispersion with direct band gaps of 1.0 eV and 0.7 eV. The band structure of the Cs₃GdCl₆ crystal consisted of 5d and 4f orbitals of Gd ions near the valence band (VB) state, the 5d orbital of Gd ions, and the 6s orbital of Cs ions near the conduction band (CB) state. The band structure of the Cs₃NdCl₆ crystal consisted of the 5p orbital of Cl ions near the VB state and the 5d orbital of Nd ions near the CB state. The charge transfer and carrier generation related to electron mobility will be caused by the overlap of the 5d orbital of Gd and Nd ions and the 6s orbital of Cs ions near the CB state. The real and imaginary parts of the dielectric function in both cases were obtained in the range of 0–1 eV. The photon energies correspond to transition between the energy levels of the split 5d and 4f orbitals of Gd and Nd ions coordinated with Cl ions as ligands in the crystal field with charge distribution. The Cs₃GdCl₆ and Cs₃NdCl₆ double perovskite crystals have high potential for the application of photovoltaic devices with photovoltaic performance.

7.6. Surface Plasma Oscillations in a Conducting Layer for a Symmetric Magnetic Field Configuration

Oleg Vladislavovich Savenko, Irina Alexandrovna Kuznetsova

• P.G. Demidov Yaroslavl State University, Yaroslavl, Russian Federation

In this work, a theoretical model of the surface plasma oscillations’ propagation in a conductive layer is constructed. We assume that the layer is located between two insulating layers with the same dielectric constants. We suppose that the surface wave frequency is much lower than the plasma resonance frequency. The case of specular reflection of charge carriers from the semiconductor layer boundaries is considered. Analytical expressions for the propagation coefficients, longitudinal, and transverse attenuation parameters are derived. An analysis of the dependencies of the surface wave parameters on the semiconductor layer thickness, surface wave frequency, and the dielectric constant of insulating layers was carried out. We established that at low frequencies (about ten THz), we observe a linear frequency dependence of the surface wave propagation coefficient. The longitudinal attenuation is practically absent, which may be due to the absence of excess charge at the layer boundaries. At a certain frequency, the longitudinal attenuation coefficient becomes non-zero, and it grows sharply with increasing frequency. The appearance of non-zero longitudinal attenuation is accompanied by a deviation of the frequency propagation coefficient dependence from the linear law. With a further increasing frequency, the propagation and attenuation parameters grow, reach a maximum, and then reduce. It follows from the above that when a non-monochromatic wave arrives at the conductive layer, a redistribution of harmonics across amplitudes occurs during surface wave propagation. This effect can be used to create plasmonic waveguides that filter frequencies, corresponding to the minimum longitudinal attenuation coefficient (plasmonic filters). We established that with rising semiconductor layer thickness and dielectric constant of insulating layers, the propagation and attenuation parameter maxima shift towards lower frequencies. Thus, by varying the thickness and selecting the material of the insulating layers with the desired optical characteristics, it is possible to change plasmonic filter pass frequency.

7.7. Nano-Enhanced Phase Change Materials Doped with Carbon Allotropes for Thermal Energy Storage: A Patent Landscape Analysis

Massimo Barrbieri

• Technology Transfer Office, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy

Nano-enhanced phase change materials (NePCMs) are composites made of an organic or inorganic PCM and nanoparticles (metal, metal oxide, carbon nanotube, graphite, graphene) capable of increasing their thermal capacity or conductivity.

PCMs are classified into three categories, namely organic, inorganic, and eutectic.

This study focuses on the patent analysis of organic NePCMs doped with carbon allotropes for thermal energy storage.

Patent searches were carried out using two databases (Espacenet, provided free of charge by the European Patent Office, and Orbit, a paid-for system provided by Questel) using precise and controlled keywords in the title/abstract/claims search fields with Boolean and proximity operators and classification codes.

Classification symbols were retrieved by means of the Espacenet classification search tool and the WIPO IPCCAT system.

China is the country with the highest number of patent applications filed for NePCMs with carbon allotropes, followed by the United States, Europe, and South Korea.

The number of patent applications filed increased from 2016 to 2022.

However, it should be noted that the figures for later years are not reliable, as applications are kept secret for the first 18 months after filing.

Graphene and its derivatives are the most frequently claimed compounds in applications and granted patents, followed by carbon nanotubes.

Fullerenes are rarely claimed (1.4% compared to graphene and derivatives), with an even smaller percentage claimed for other nanosized carbon materials (such as nano-onions, nanoscrolls, nanohorns, nanocones, nanowalls, and nanocoils).

Approximately 30% of the applications have either expired or been revoked or withdrawn.

Of the active patents, between 35% (for nanotubes) and 40% (for graphene) remain under examination.

The most commonly used PCMs in combination with carbon allotropes are paraffin, stearic and lauryl acids, and lauryl alcohol.

7.8. Lithium Adsorption Properties of Two-Dimensional Chromium Nitride

Amretashis Sengupta

• Department of Physics, P.D. Women’s College (affiliated to University of North Bengal)

Two-dimensional (2D) materials promise improved performance and energy storage capacities in next-generation Li-ion batteries due to their large surface area, enhanced specific capacity, and quick ion diffusion coupled with light weight and flexibility. Two-dimensional CrN is a recently proposed novel 2D material showing interesting properties regarding ferromagnetism, optical transparency, and good elastic properties, as well as catalytic and gas-sensing properties in free-standing or heterostructure form combined with other 2D materials. This study examines the lithiation characteristics of 2D CrN sheets with density functional theory (DFT) calculations. Using Perdew–Burke–Ernzerhoff (PBE) DFT calculations with the Generalized Gradient Approximation (GGA), we computed the various parameters for Li adsorption on 2D CrN. We carried out structural optimization calculations with the Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm for the adsorption studies and performed a climbing-image-nudged elastic band calculation to evaluate the diffusion barriers. In all calculations, the van der Waals forces were taken into consideration, with Grimme’s DFT-D3 correction scheme. In our studies, 2D CrN demonstrated an excellent theoretical specific capacity up to 1322.73 mAhg⁻¹, a small electrode potential of about 0.2 V, and a diffusion barrier of 0.17 eV. According to the calculations, 2D CrN might be used as a substitute anode material in Li-ion storage.

8. Crystalline Metals and Alloys

8.1. Data-Led Analysis and Feature-Based Modelling of Critical Phases in the Dissimilar Welding of Duplex Stainless Steel

Huan Miao ^1,2, Muhammad Safwan Mohd Mansor ¹, Sufian Raja ¹, Tammy Kaid ², Xiaochun Zhan ³, Fatih Ateş ⁴ and Farazila Yusof ¹

¹ 

Department of Mechanical Engineering, Faculty of Engineering, Universiti Malaya, Kuala Lumpur, 50603, Malaysia

² 

Faculty of Engineering and Technology, James Parsons Building, Liverpool John Moore’s University, 3Byrom St, Liverpool L3 3AF, United Kingdom

³ 

SISU Xianda College, Shanghai, China

⁴ 

Ermetal Otomotiv, Bursa, Türkiye

Duplex stainless steel (DSS) with a mixed ferrite–austenite structure is an advanced stainless-steel group with mechanical properties and corrosion resistance superior to those of single-phased steels. The dissimilar welding of DSS, between different grades of DSSs and with other material groups, is an active research area with huge importance for DSS applications. However, the complex composition of the alloying system may naturally lead to complicated phase structures, either in isolated form or as connected zones. This directly affects the structure integrity, weldability, corrosion resistance, and aesthetic appearance of stainless steels. The phase structure could also cause complex issues for developing microstructure-based models for different material groups. This work critically reviews and analyses recent developments and data on the dissimilar welding of DSSs, including welding between different groups, such as DSS, Super DSS, and Lean DSS, as well as welding of DSSs with carbon steels, high-strength steels, single-phased stainless steels, and other nonferrous alloys with/without filler alloys. Feature analysis is conducted on the key welding zones, and the main phases, including precipitation phases and intermetallic, primary, and secondary boundaries, are identified. Data analysis is conducted to classify the phase zones formed in the welding of different materials. A microstructural map of the location of intermetallic and secondary phases/zones in different weldments is presented and used to develop feature-based parametric finite element models. The effect of some key features of the phase zones/boundaries (e.g., martensite and intermetallic) on the structural integrity of the weldments is discussed.

8.2. Three-Dimensional Characterization of Fe-Rich Intermetallics in Al-Si-Mg (A6xxx) Aluminium Alloy DC Cast Billets with an Increased Scrap Content by X-Ray Tomography

Jaime Lazaro Nebreda ¹, Pavel Shurkin ¹, Tungky Subroto ², Carla Barbatti ², Geoff Scamans ¹

¹ 

BCAST, Brunel University London

² 

Constellium University Technology Centre, Brunel University London

The characterization of Fe-rich intermetallic compounds (Fe-IMCs) in DC-casting billets of aluminium alloys is critical for understanding their downstream processing and the properties of the final components. The use of recycled aluminium scrap in the formulation of these alloys results in the accumulation of Fe and other elements and modifies the volume fraction, the size, and the shape of these Fe-IMCs. Standard techniques, like optical or electronic microscopy, allow for 2D visualization and quantitative comparison but do not provide enough information about the real 3D morphology of the intermetallics or the connectivity between them. In this study, we have used X-ray computed tomography to evaluate the 3D features of the intermetallics in DC billets for an Al-Si-Mg alloy with different levels of Fe in the as-cast and homogenized conditions. The 3D analysis shows that increasing Fe in the alloy results in thicker, more elongated, and more interconnected particles, while during homogenization, the particles become thinner and more rounded and fragmented. We also provide a detailed comparison between the 2D and 3D results. The use of real 3D morphology characteristics of the secondary phases is more accurate and will allow for a better understanding of the solidification process for DC billets in industry, as well as the subsequent microstructure and the properties of the extruded components.

8.3. Mineralogical Studies of Low-Grade Iron Ores from Daitari Iron Ore Deposit, Odisha, India

Jayant Kumar Sahoo

• Ravenshaw University, Cuttack, Odisha

Iron is one of the most important metallic elements and covers around 5.05% of the Earth’s crust. It has widespread applications in our day-to-day life, from household equipment to large industries. Due to rapid increases in the demand for steel in both the global and domestic market, as well as due to an ongoing depletion of high-grade iron ores, industry actors and policy makers have started considering the utilization of low-grade iron ores. According to the National Steel Policy 2017, India aims to attain a steel production capacity of 300 MT by 2030. In order to achieve this target, we must improve the utilization of low-grade iron ores. In this study, we use a low-grade iron ore, specifically banded hematite jasper (BHJ) from Daitari Iron Ore Mines, Odisha, India. The aim of this study is to understand the morphology, mineralogy, texture, and chemistry of BHJ. The characterization of BHJ is carried out using X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), optical microscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The XRD results suggest that quartz is the major gangue mineral, while hematite is the major iron mineral. The XRF analysis shows that the Fe content of BHJ is around 30%, and its SiO₂ content is around 54%, along with minor elements in varying proportions. Optical microscopic studies indicate the presence of alternate bands of hematite and quartz in BHJ, while SEM-EDS demonstrates how iron and silicate phases are associated with each other. This study allows for the optimization of conventional liberation or beneficiation practices for low-grade iron ores.

8.4. Energy Distribution in Iron Nano-Spheres with Cubic Magneto-Crystalline Anisotropy

Pawel Steblinski ¹, Tomasz Blachowicz ^1,2, Andrea Ehrmann ^1,3

¹ 

Virtual Institute of Applied Research on Advanced Materials (VIARAM)

² 

Institute of Physics—Center for Science and Education, Silesian University of Technology, 44-100 Gliwice, Poland

³ 

Institute for Technical Energy Systems (ITES), Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences and Arts, 33619 Bielefeld, Germany

Magnetic memory systems are one of the recently strongly investigated topics in the research area of spintronics. Amongst the different data storage systems, magnetic nanoparticles are of high interest since they can often store large amounts of data on small scales. Such magnetic nanoparticles, however, pose new challenges, such as oxidation and agglomeration. Here, we show micromagnetic simulations using MagPar, which solves the Landau–Lifshitz–Gilbert equation using finite elements, to analyse the energy density of iron nano-spheres. For spheres of 10 nm or 25 nm and different oxide shell thicknesses, 3D energy maps were calculated. Interestingly, the cubic magneto-crystalline anisotropy led to a non-uniform energy distribution of the magnetic nano-spheres, with the number of extrema decreasing for larger oxide layer thicknesses. In the case of the agglomeration of four nano-spheres, the distances between the nano-spheres strongly modified the system’s magnetic properties, where an oxide shell enabled bringing the nano-spheres closer together before they start influencing each other, which was evaluated by comparing the magnetic properties of these agglomerates with the single nano-spheres. For the oxide-coated system, the maximum packing density could be increased by about 12%, as compared to the non-coated system, indicating that a higher data density can be reached by preparing a matrix of magnetic nano-spheres with oxide shells.

8.5. Optical and Pressure-Induced Investigations of Double Perovskite Ba₂TiMnO₆ from the First Principles

Thi Thu Ha Nguyen ¹, Mane Sahakyan ² and Vinh Hung Tran ²

¹ 

Doctoral School, University of the National Education Commission, Podchorążych 2, 30-084 Kraków, Poland

² 

Institute of Low Temperature and Structural Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland

Double perovskite (DP) compounds have been reported to possess many valuable properties and are considered excellent candidates for magnetocaloric applications, high-performing semiconductivity in optoelectronic devices, and photo(electro)chemical energy storage systems [54,55,56,57]. To explore the physical properties of double perovskite Ba₂TiMnO₆, we examined its optical and pressure dependence utilizing PBE-GGA and PBE-GGA+U exchange–correlation energy functionals. Following previous findings, DFT calculations revealed direct semiconducting band gaps of 0.82, 0.98, and 1.27 eV, respectively [58]. Moreover, the optical properties show high dielectric constants, a robust light absorption coefficient in the UV energy range, and a significant optical conductivity of 6.53 × 105 cm⁻¹, making Ba₂TiMnO₆ a promising candidate for high-performance perovskite solar cells in optoelectric applications. We identified that optical properties below 10 eV are mostly due to intraband and interband transitions of Mn-3d electrons. Employing the Projected Augmented Wave (PAW) method, we also studied the impact of pressure on crystal structure and density of states. Notably, near 8 GPa, there appears to be a structural distortion, accompanied by a sharp increase in the semiconducting gap.

8.6. Integrated Data-Led Modelling of M7C3 Carbides Alloys

Tammam Bader Kaid ¹, xiaoliang Qing ², Cong Tang ², li wang ³, Ariyan Ashkanfar-Appleton ², Hongming Liu ⁴, Qingxiang Yang ⁵ and James Ren ¹

¹ 

School of Engineering, Liverpool John Moores University

² 

Liverpool John Moores University, Liverpool, UK

³ 

Queen Mary-University of London, London, UK

⁴ 

University of Science and Technology Lanzhou, Lanzhou, China

⁵ 

Yanshan University, Qinhuangdao, China

M7C3 carbides (where M could be Fe, Cr, i.e., (Fe, Cr)7C3) or other solution elements replacing Cr or Fe are a special group of carbides, widely used in materials such as white cast iron and welded hard facings. Normally, the structure of hypereutectic Fe–Cr–C alloy consists of a high quantity of large primary M7C3 carbides within a eutectic matrix. The morphologies of primary M7C3 carbides directly influence the hardness, wear resistance, and fracture toughness of the alloy, as well as the physical properties such as thermal conductivity and electrical resistance. It is essential to develop a systematic data-led modelling framework to assess the effect of the morphologies on the key properties and functionalities of M7C3 carbides under different loading conditions.

In this paper, microstructure-based modelling is applied to M7C3 carbides. An effective framework has been developed to transfer the microstructure of M7C3 carbides into image databases for statistical structure analysis and modelling. A mechanical–thermal–electrical modelling approach has been developed and is applied to different carbide structures for predicting the effective properties, including stiffness, thermal, and electrical properties. A new approach is developed to model the structure of individual carbides, including the stress concentration factors associated with the shapes and the internal features, which is critical to the wear and fracture of the carbides. The key functional features of the program are presented, including microstructure data, image processing, and structure models with different scales. The work shows that the internal feature could cause significant variation in stress concentration factors under different loading and boundary conditions. The key issues in data development and analysis of the structures are outlined. The link between engineering simulation and first-principle calculation of the properties is analysed. The use of modelling for data-driven materials development and quality and performance prediction is discussed.

8.7. Data-Led Modelling and Analysis of Defects and Doping in Different Carbides

Xiaoliang Qing ¹, Xiaoxiao Liu ², Jing Guo ³, Tammy Kaid ⁴, Qian Zhang ⁴, Cong Tang ^4,5, li wang ⁶, Hongming Liu ⁷, Qingxiang Yang ⁸ and James (Xuejun) Ren ²

¹ 

School of Engineering, Liverpool John Moores University, Liverpool, UK

² 

Liverpool John Moores University, Liverpool, UK

³ 

The University of Manchester, Manchester, UK

⁴ 

Liverpool John Moores University, Liverpool, UK

⁵ 

Jaguar Land Rovers, UK

⁶ 

Queen Mary-University of London, London, UK

⁷ 

University of Science and Technology, Lanzhou, China

⁸ 

Yanshan University, Qinhuangdao, China

Point and complex defects and doping play important roles in the mechanical and physical properties and functionality of crystalline materials such as carbides. First-principle calculations of defects/doping based on density functional theory have been widely used as an effective tool for studying the influence of defect and doping elements, which is important for understanding the evolution of precipitated carbides and the development of high-performance carbides. In this study, the first-principle method is adapted to establish data for two typical carbides—Ni4C and Mo2C in 2D and 3D structures. A systematic approach has been developed for studying and analysing the effects of a range of doping elements and different types of defects on the mechanical, electronic, and magnetic properties.

Calculations show that there is an enhancement in the magnetism of the Mo2C structure when doped with Co and Mn, which may be due to the doping elements of changing the electronic structure of Mo2C, introducing local magnetic moments. Data with Co and Mn doping in Ni4C also indicate an increase in the magnetic moment and enhancement of the magnetic performance. In addition, a change in the magnetic data of Mo2C is observed with some types of vacancy defects and asymmetric structure. The comparative analysis of data for 2D and 3D structures of Mo2C shows that the 2D structure has different characteristics from the 3d structure when doped. These results further contribute to the understanding of effects of defects and doping elements on the mechanical and physical properties, in particular the magnetism of carbides. The potential link between the data to the understanding of carbide formation and their use in new emerging areas is analysed. The issues and use of the data in integrated approaches combining modelling, experimental, and data analysis are discussed.

8.8. Experimental and Computational Methods for Determining the Composition of Commercial Titanium and Aluminum Alloys

Galina Kuzmicheva ¹, Andrey Dolgov ² and Ivan Pavlov ³

¹ 

MIREA—Russian Technological University

² 

MIREA—Russian Technological University, Vernadsky pr., 78, Moscow, 119454, Russian Federation

³ 

Kurchatov Complex of Crystallography and Photonics, National Research Center “Kurchatov Institute”, Leninsky pr., 59, Moscow, 119333, Russian Federation

Commercial alloys of Al-1 (wt.%) (91.9–94.6Al, 4.8–5.8Mg, 0.5 Si = Fe, 0.1Cu, 0.05–0.08Mn, 0.005Be), Al-2 (90.8–94.7Al, 1.2–1.8Mg, 0.5Si = Fe, 3.8–4.9Cu, 0.3–0.9Mn, 0.1Ni), and Ti (94.2–96.9Ti, 1.0–2.5Al, 0.15Si, 0.3Fe, 0.3Zr, 0.7–2.0Mn, 0.15O, 0.3X) contain impurities but bear no indication of their composition and structure, on which the performance characteristics of the materials depend. The purpose of this work was to develop a method and program for determining the alloys’ composition. The use of a complex of X-ray phase and elemental (EDX) analyses and crystal chemical calculations (the theory of closest packing—CP, metal radii—r(M)Å, and Vegard’s—V, or Retger’s—R rules) allowed us to determine the compositions of these alloys.

Al-1. Substitutional solid solution (SSS) (Al_1−xMg_x) (sp.gr. Fm3m; a_exp = 4.088(7)Å) with type (ST) of Cu (98%) + impurities (2%): a_CP(Al) = 4.045 Å, “a_CP(Mg)” = 4.526 Å—(Al_0.90Mg_0.10)_CP+V (~350 °C) [59]; EDX (wt.%): 91Al, 8Mg, 0.2Fe, 0.3Si, 0.5Mn.

Al-2. SSS (Al_1−xCu_x) (STCu; a_exp = 4.036(4) Å): a_exp(Al) = 4.049 Å, a_exp(Cu) = 3.615 Å; a_CP(Al) = 4.045 Å, a_CP(Cu) = 3.620 Å—(Al_0.97Cu_0.03)_V = (Al_0.98Cu_0.02)_CP+V (~500 °C) [60]; EDX (wt.%): 98.3Al, 0.7Mg, 0.3Fe, 0.4Si, 0.1Mn, 0.1Cu, 0.1Ni.

Ti. SSS (Ti_1−xAl_x) (sp.gr. P6₃ /mmc; a_exp = 2.942, c_exp = 4.678 Å, c/a = 1.590, V = 35.064 ų) with ST derived from Mg (c/a = 1.633): a_exp(Ti) = 2.950Å, c_exp(Ti) = 4.684 Å, V = 35.300 ų; a_CP(Ti) = 2.940 Å, c_CP(Ti) = 4.675 Å, V_CP = 34.994 ų; “a_CP(Al)” = 2.860 Å, “c_CP(Al)” = 4.547 Å, V_CP = 32.208 ų—(Ti_0.92Al_0.08)_CP+R; “a_CP(Mn)” = 2.540 Å, “c_CP(Mn)” = 4.039 Å, V_CP = 22.566 ų—(Ti_0.98Mn_0.02)_CP+R; (Ti_1.00–0.80Al_0–0.12Mn_0–0.08) (700 °C) [61]; EDX (wt.%): 84.6Ti, 2.5Al, 1.0Mn, 0.2Si, 0.1Fe, 11.6O.

Thus, the composition of Al-1, Al-2, and Ti alloys are different from those indicated by the certificates.

Funding: Ministry of Science and Higher Education of the Russian Federation grant № FSFZ-2024-0003.