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Volume 7
Issue 2
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Chemistry, Volume 7, Issue 2 (April 2025) – 38 articles

Cover Story (view full-size image): Quinoidal structures contain a diradical character and possess characteristic electronic properties, including multiple redox systems and absorption bands in visible and near-infrared regions. Consequently, quinoids are significant structural motifs in organic materials, and considerable efforts have been made to develop synthetic methods for quinoid compounds. Dearomative cycloaddition is an effective approach for constructing quinoid compounds from readily available aromatic compounds. Herein, we report a photochemical dearomative cycloaddition of corannulene with an isolable dialkylsilylene (silicon analogue of carbene) to furnish a π-expanded o-quinodimethane derivative. We discuss the structure, electronic properties, and reactions of the product. View this paper
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11 pages, 3188 KiB  
Article
Interaction Between Iso-α-Acid Extracted from Hops and Protein Z Improves Beer Foam Quality and Stability
by Canyan Chen and Chenyan Lv
Chemistry 2025, 7(2), 65; https://doi.org/10.3390/chemistry7020065 - 19 Apr 2025
Viewed by 103
Abstract
Foam quality is an important index for judging the quality of beer. In this experiment, the interaction between PZ and iso-α-acid extracted from hops and its effect on beer foam production were investigated. According to the results of fluorescence titration experiments, the stoichiometric [...] Read more.
Foam quality is an important index for judging the quality of beer. In this experiment, the interaction between PZ and iso-α-acid extracted from hops and its effect on beer foam production were investigated. According to the results of fluorescence titration experiments, the stoichiometric number ratio of PZ interacting with iso-α-acid was 3.91 ± 0.39, and the binding constant K was (2.16 ± 0.23) × 105 M−1. According to the results of molecular dynamics simulations, the binding sites of iso-α-acid in PZ were Leu-396, Ser-292 and Lys-290. The secondary structure of PZ was altered by the addition of iso-α-acid, and the percentage of β-sheets increased from 21.75% to 29.74%. which increased the protein’s flexibility, leading to enhanced foaming, stability, and texture of the foam. Full article
(This article belongs to the Section Food Science)
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18 pages, 6139 KiB  
Article
Spectrophotometric Assessment of 5-HMF in Thermally Treated Honey: Analytical Performance Comparison of Classical and Modified Methods
by Dalma Fazakas and Augustin C. Mot
Chemistry 2025, 7(2), 64; https://doi.org/10.3390/chemistry7020064 - 16 Apr 2025
Viewed by 153
Abstract
To ensure high-quality honey, and to delay crystallization or fermentation, honey is subjected to heat treatment. The heating process, as well as the duration and storage conditions, can lead to an increased level of 5-HMF (5-hydroxymethylfurfural), which exhibits numerous adverse effects on human [...] Read more.
To ensure high-quality honey, and to delay crystallization or fermentation, honey is subjected to heat treatment. The heating process, as well as the duration and storage conditions, can lead to an increased level of 5-HMF (5-hydroxymethylfurfural), which exhibits numerous adverse effects on human health. The objective of the present study was to evaluate the evolution of 5-HMF levels in different varieties of honey from Romania, thermally treated at different temperatures between 45 and 75 °C. Both classical spectrophotometric methods, such as White and Winkler methods, and two modified simpler methods were used. The methods were compared based on their analytical reactions and analytical parameters such as linearity, LOD and LOQ, sensitivity, accuracy, and precision. The best-performing method was the one that employed thiobarbituric acid. The level of 5-HMF in the control samples and samples treated at 45 °C are below the limits accepted by the legislation (40 mg/kg). At higher temperatures, such as 55–65 °C, the values in some honey species, especially polyfloral species, already exceed the accepted threshold (57.5 ± 0.7 mg/kg; 98.8 ± 4.6 mg/kg) whereas at 75 °C, the 5-HMF level is very high (142.8 ± 8.7 mg/kg; 453.8 ± 51.3 mg/kg). The results obtained indicate that 5-HMF level increases gradually with temperature and is variety dependent. Full article
(This article belongs to the Section Food Science)
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14 pages, 2500 KiB  
Article
Dynamical Resolution of QM/MM Near-UV Circular Dichroism Spectra of Low-Symmetry Systems
by Jérémy Morere, Tanguy Leyder, Catherine Michaux, Claude Millot, Emmanuelle Bignon and Thibaud Etienne
Chemistry 2025, 7(2), 63; https://doi.org/10.3390/chemistry7020063 - 16 Apr 2025
Viewed by 176
Abstract
Near-UV circular dichroism (CD) spectroscopy is a widely used method that provides, among others, information about the tertiary structure of biomolecular systems such as proteins, RNA, or DNA. Experimental near-UV CD spectra of proteins reflect the CD signals averaged over the many conformations [...] Read more.
Near-UV circular dichroism (CD) spectroscopy is a widely used method that provides, among others, information about the tertiary structure of biomolecular systems such as proteins, RNA, or DNA. Experimental near-UV CD spectra of proteins reflect the CD signals averaged over the many conformations that these systems can adopt. Theoretical approaches have been developed to predict such spectroscopic properties and link modeled conformations of complex biosystems to easily accessible experimental data, without having the resort to costly structural biology techniques. However, these predictions are mostly generated on the basis of a single experimental structure, missing the dynamic information reflecting the protein conformational variability. Here, we describe a complete reformulation of the theoretical foundations behind the prediction of CD spectra. We propose a QM/MM-based automated pipeline that generates an average near-UV CD spectrum from a given MD ensemble in a fast manner based on these theoretical considerations and further test it on protein systems. This pipeline has been implemented in an open-source program called DichroProt. Full article
(This article belongs to the Section Theoretical and Computational Chemistry)
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10 pages, 2365 KiB  
Article
Remarkably Efficient [4+4] Dimerization of [n]-Cyclacenes
by Ankit Somani, Divanshu Gupta and Holger F. Bettinger
Chemistry 2025, 7(2), 62; https://doi.org/10.3390/chemistry7020062 - 12 Apr 2025
Viewed by 195
Abstract
Cyclacenes with the general formula C4nH2n are cyclic analogs of acenes. Acenes are well-known for their high reactivity, which increases with the number of fused benzene rings. The cyclic strain, absence of a Clar sextet, and diradical or [...] Read more.
Cyclacenes with the general formula C4nH2n are cyclic analogs of acenes. Acenes are well-known for their high reactivity, which increases with the number of fused benzene rings. The cyclic strain, absence of a Clar sextet, and diradical or polyradical nature are expected to render cyclacenes highly reactive under ambient conditions. Their primary decomposition pathway is anticipated to involve dimerization or polymerization. We explore the reaction pathway of the [π4s + π4s] dimerization of [n]-cyclacenes for 6 ≤ n ≤ 20 by density functional theory (DFT) using spin-unrestricted and thermally-assisted-occupation (TAO) formalisms. Computational analysis predicts a stepwise reaction mechanism that starts with the formation of a van der Waals complex and proceeds through a transition state to an intermediate with a single new C–C bond and two unsaturated valences. A subsequent second transition state results in the formation of the dimerization product. However, for smaller cyclacenes (n < 10), neither the van der Waals complex nor the first transition state is involved, and the intermediate is formed without a barrier. The largest [20]-cyclacene investigated exhibits the highest barriers for these processes. However, with a barrier as low as 3.9 kcal/mol at the UB3LYP-D3(BJ)/6-31G(d) level of theory, dimerization is anticipated to occur very rapidly. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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39 pages, 4555 KiB  
Review
Types of Crosslinkers and Their Applications in Biomaterials and Biomembranes
by Paolo Yammine, Ali El Safadi, Rima Kassab, Hanna El-Nakat, Pierre J. Obeid, Zeina Nasr, Tony Tannous, Nouha Sari-Chmayssem, Agapy Mansour and Ayman Chmayssem
Chemistry 2025, 7(2), 61; https://doi.org/10.3390/chemistry7020061 - 11 Apr 2025
Viewed by 487
Abstract
Biomaterials and biomembranes play a crucial role in a variety of applications, particularly in the medical field due to their ability to mimic natural biological structures and functions. Crosslinkers play also an important role in enhancing the structural integrity and functionality of biomaterials [...] Read more.
Biomaterials and biomembranes play a crucial role in a variety of applications, particularly in the medical field due to their ability to mimic natural biological structures and functions. Crosslinkers play also an important role in enhancing the structural integrity and functionality of biomaterials and in the design of biomembranes. This review article explores the fundamentals of biomaterials and biomembranes, with a particular focus on the role of crosslinkers in biology, chemistry and medicine. We explore the various types of crosslinkers commonly used in biomaterials synthesis, examining their chemical structure, classification, and synthesis methods. Additionally, we analyze the biological properties of crosslinkers and their interactions, highlighting their biological impact, particularly in cellular behavior and cytotoxicity. This article further emphasizes recent advances and innovation, particularly in tissue engineering, drug delivery, and wound healing. Finally, we conclude by addressing current challenges and suggesting potential futures directions for research in this field. Full article
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14 pages, 3609 KiB  
Article
Morphology and Composition of Brake Wear Particles Ameliorated by an Alumina Coating Approach
by Ran Cai, Jingzeng Zhang and Xueyuan Nie
Chemistry 2025, 7(2), 60; https://doi.org/10.3390/chemistry7020060 - 4 Apr 2025
Viewed by 330
Abstract
A plasma-assisted electrochemical deposition (PAECD) technology was introduced to coat a cast iron brake disc for the possible reduction of brake wear and brake wear particle (BWP) emission. The majority of the coating consisted of alumina (Al2O3), determined by [...] Read more.
A plasma-assisted electrochemical deposition (PAECD) technology was introduced to coat a cast iron brake disc for the possible reduction of brake wear and brake wear particle (BWP) emission. The majority of the coating consisted of alumina (Al2O3), determined by energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) analysis. To validate the above strategy of the coating technology for automotive brake corners, one brake stock rotor was replaced by a PAECD-coated rotor for a vehicle road test. After the road test, weight loss of the brake components (rotors and pads) was measured, showing that the alumina coating can reduce the brake wear by more than 70%. BWPs were also collected from wheel barrels, spokes, and brake friction rings of the coated and uncoated rotors during the road test. A morphology and chemical composition analysis of the collected BWPs indicated that the coating could reduce BWP generation from the original sources and avoid a metal pick-up (MPU) issue, leading to less metallic content in BWPs. This alumina coating may provide the auto sector with a sustainable approach to overcome the brake dust emission problem, evidenced by less wear of the brake pads, minimal wear of the coated brake rotor, less MPUs, and a clean wheel rim on the coated brake corner. Full article
(This article belongs to the Section Green and Environmental Chemistry)
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9 pages, 2051 KiB  
Article
Beyond L-Proline: Investigation into the Catalytic Properties of Other Natural Amino Acids in an Organocatalytic Warfarin Synthesis
by Anna I. Wurz, Arhemy Franco-Gonzalez, Naomi R. Benson, Hope L. Jankowski, Sierra N. Carr, Ketan Chamakura, Lizbeth Chirinos, Sydney P. Coll, Kayla F. Ivory, Trinity J. Lamb, Shaya LeBauer, Grace L. McPherson, Thanh Nguyen, Jeimy Nolasco Guevara, Lily N. Parsad, Phuong Pham, Emma G. Piner, Kaci Richardson, Abdelhadi Bendjellal, Chelsea McRae and Robert M. Hughesadd Show full author list remove Hide full author list
Chemistry 2025, 7(2), 59; https://doi.org/10.3390/chemistry7020059 - 4 Apr 2025
Viewed by 313
Abstract
Proline is considered the model organocatalytic amino acid. However, other naturally occurring amino acids remain a potent and perhaps overlooked source of organocatalytic potential. In this work, we investigated the capacity of various natural amino acids to promote enantioselectivity in a synthesis of [...] Read more.
Proline is considered the model organocatalytic amino acid. However, other naturally occurring amino acids remain a potent and perhaps overlooked source of organocatalytic potential. In this work, we investigated the capacity of various natural amino acids to promote enantioselectivity in a synthesis of warfarin. We have identified L- and d-arginine as enantioselective catalysts for this reaction and have developed a recrystallization method to isolate the enantiomers of warfarin with high enantiopurity. In addition, we used methylated derivatives of arginine to provide insight into the reaction mechanism. Full article
(This article belongs to the Topic Towards the Sustainable Synthesis of Biologically Active Molecules in Green Solvents)
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15 pages, 3935 KiB  
Article
Comparative Analysis of Chemical Profiles and Bioactive Properties in Six Pigmented and Non-Pigmented Rice Varieties
by Nari Yoon, Youngrok Kim, Joong Hyoun Chin and Sanghyun Lee
Chemistry 2025, 7(2), 58; https://doi.org/10.3390/chemistry7020058 - 3 Apr 2025
Viewed by 258
Abstract
This study presents a comprehensive analysis of the chemical composition and bioactive properties of six newly cultivated varieties of pigmented and non-pigmented rice: Neunkeunheukchal (NKH), Neunkeunssal, Heukjagwang 709 (H709), Heukjagwang 1601, Hongjinju, and Hongchapssal (HCS). This study aims to characterize the chemical information [...] Read more.
This study presents a comprehensive analysis of the chemical composition and bioactive properties of six newly cultivated varieties of pigmented and non-pigmented rice: Neunkeunheukchal (NKH), Neunkeunssal, Heukjagwang 709 (H709), Heukjagwang 1601, Hongjinju, and Hongchapssal (HCS). This study aims to characterize the chemical information and the industrial potential of lesser-known rice varieties. Significant differences were observed in the levels of phenolic compounds, flavonoids, γ-oryzanol, and free amino acids among these varieties, correlating with their antioxidant capacities. Among these varieties, NKH consistently exhibited the highest total phenolic, flavonoid, and γ-oryzanol contents, along with the strongest radical-scavenging activities, indicating its potential as a valuable functional food ingredient. Additionally, H709 and HCS demonstrated significant antioxidant activities, highlighting their potential roles in health-promoting applications. These findings highlight the potential of these varieties for functional food and nutraceutical applications. Future research should investigate the effects of cultivation conditions and processing methods on bioactive compound levels while conducting clinical trials to validate these health benefits in human models. The findings suggest that NKH, given its rich bioactive profile, may be particularly effective in managing oxidative stress and associated chronic diseases. Furthermore, the γ-oryzanol contents, the highest in NKH, highlight its potential for metabolic health benefits. This study lays the groundwork for future investigations into the development of functional foods and nutraceuticals derived from the unique characteristics of pigmented and non-pigmented rice varieties. Full article
(This article belongs to the Topic Exploring the Interplay of Agriculture, Analytical Chemistry, Environments and Toxics)
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24 pages, 5355 KiB  
Article
Complexation of Lanthanides(III) Ions with Terephthalic Acid in Aqueous Solutions by Potentiometric Titration Combined with Photoluminescence Spectroscopy
by Polina B. Guseva, Alexander R. Badikov, Oleg S. Butorlin, Yulia N. Toikka, Sergey N. Orlov, Mikhail N. Ryazantsev, Nikita A. Bogachev, Mikhail Yu. Skripkin and Andrey S. Mereshchenko
Chemistry 2025, 7(2), 57; https://doi.org/10.3390/chemistry7020057 - 3 Apr 2025
Viewed by 243
Abstract
The complexation behavior of lanthanide(III) ions with terephthalic acid (1,4-benzene-dicarboxylic acid) in 0.01 M KNO3 aqueous solutions was studied across a broad pH range and at two metal-to-ligand ratios using potentiometric titration combined with photoluminescence spectroscopy. Chemometric analysis of titration curves enabled [...] Read more.
The complexation behavior of lanthanide(III) ions with terephthalic acid (1,4-benzene-dicarboxylic acid) in 0.01 M KNO3 aqueous solutions was studied across a broad pH range and at two metal-to-ligand ratios using potentiometric titration combined with photoluminescence spectroscopy. Chemometric analysis of titration curves enabled the determination of relative molar fractions, stability constants, and probable stoichiometry of the formed complexes. In solutions with a 1:2 metal-to-ligand ratio, bis-complexes (two terephthalate ligands per lanthanide ion) predominated, while ligand-rich conditions favored the formation of tetra-complexes (four ligands per metal ion). In alkaline media, bis-complexes transform into mixed hydroxy-terephthalate species. Meanwhile, for the tetra-complexes, the addition of NaOH results in the formation of lanthanide ion hydroxo complexes without organic ligands. The structural diversity of these complexes, driven by the terephthalate ligand’s tendency to maximize denticity, suggested dimeric or oligomeric configurations. The stability constants and structural features of complexes in solution were found to align with those of known solid-state lanthanide–terephthalate polymers, highlighting their potential as models for polymeric structures. Full article
(This article belongs to the Section Physical Chemistry and Chemical Physics)
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10 pages, 2393 KiB  
Article
Density Functional Theory Simulations of Skaergaardite (CuPd) with a Self-Consistent Hubbard U-Correction
by Martino Napoli and Assimo Maris
Chemistry 2025, 7(2), 56; https://doi.org/10.3390/chemistry7020056 - 2 Apr 2025
Viewed by 282
Abstract
The electronic and phonon bands of Skaergaardite are investigated using density functional theory (DFT) as implemented in Quantum ESPRESSO. Skaergaardite is a copper palladium mineral (CuPd) found in the Skaergaard intrusion with a CsCl-type (B2) structure. Due to its porous structure, it presents [...] Read more.
The electronic and phonon bands of Skaergaardite are investigated using density functional theory (DFT) as implemented in Quantum ESPRESSO. Skaergaardite is a copper palladium mineral (CuPd) found in the Skaergaard intrusion with a CsCl-type (B2) structure. Due to its porous structure, it presents a large surface area available for interactions, which makes it a promising catalyst. The PBE-GGA functional with a Hubbard-like localized term (DFT+U) is combined with ultrasoft and norm-conserving pseudopotentials, and a conventional approach with a dense Monkhorst–Pack grid of k-points 12 × 12 × 12 is applied. The electronic valence bands are mainly constituted by 3d orbitals of Cu and 4d orbitals of Pd and a pseudo-gap can be recognized. With respect to DFT, DFT+U causes a general downward shift in the valence band. The acoustic and optical phonon branches are separated by a few cm−1 gap at about 150 cm−1 and show a density of state curve typical of ordered materials. These results highlight the reliability of DFT+U in studying bimetallic systems with scarce experimental benchmarks, offering insights into the behavior of Skaergaardite and its potential applications in material science such as reduction reactions and hydrogen storage. Full article
(This article belongs to the Section Chemistry of Materials)
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8 pages, 2603 KiB  
Communication
Carbon-Rich Selenide Monolayers as Metal-Free Catalysts for Oxygen Reduction Reactions: A First-Principles Investigation
by Yao Xu and Fengyu Li
Chemistry 2025, 7(2), 55; https://doi.org/10.3390/chemistry7020055 - 1 Apr 2025
Viewed by 202
Abstract
Carbon-based materials have garnered significant attention for electrocatalysis applications in fuel cells due to their unique structural and electronic properties, but rapid oxygen reduction reaction (ORR) at the cathode of fuel cells is challenging. Dopants are typically used as active sites for ORR, [...] Read more.
Carbon-based materials have garnered significant attention for electrocatalysis applications in fuel cells due to their unique structural and electronic properties, but rapid oxygen reduction reaction (ORR) at the cathode of fuel cells is challenging. Dopants are typically used as active sites for ORR, and increasing the number of active sites for carbon-based catalysts remains a challenge. Here, we carried out first-principles calculations for the electrocatalytic ORR performance of the recently reported monolayer superconductors of carbon-rich selenides. Remarkably, the abundant C atoms serve as the active centers instead of the foreign atoms (Se). All the free energy changes during the ORR process are downhill, suggesting that these carbon-rich selenides hold promise as metal-free electrocatalysts for ORR. Note that the promising electrocatalytic performance of carbon-rich selenides is theoretically predicted; validation is encouraged for experimental efforts. Full article
(This article belongs to the Section Theoretical and Computational Chemistry)
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24 pages, 6282 KiB  
Article
Study on the Effect of Different Cathodic Protection Potentials on the Growth of Mixed Bacteria and Cathodic Protection Efficiency
by Zeyu Zuo, Jie Zhang, Qingle Hou, Chengjun Zhang, Ke Wang, Jizhou Duan, Xilei Chen and Baorong Hou
Chemistry 2025, 7(2), 54; https://doi.org/10.3390/chemistry7020054 - 1 Apr 2025
Viewed by 235
Abstract
Microbiologically influenced corrosion (MIC) is one of the key causes of material failure in marine engineering, and sulfate-reducing bacteria (SRB) and iron-oxidizing bacteria (IOB) are typical representatives of anaerobic and aerobic microorganisms, respectively. These microorganisms are widely present in marine environments and can [...] Read more.
Microbiologically influenced corrosion (MIC) is one of the key causes of material failure in marine engineering, and sulfate-reducing bacteria (SRB) and iron-oxidizing bacteria (IOB) are typical representatives of anaerobic and aerobic microorganisms, respectively. These microorganisms are widely present in marine environments and can form synergistic communities on the surface of metal materials, posing a corrosion threat to them. At the same time, the presence of mixed bacteria may have an effect on cathodic protection, so this study investigates the growth metabolism of mixed SRB and IOB under different cathodic protection potentials in an impressed current cathodic protection (ICCP) system in a marine environment containing SRB and IOB. It also examines the attachment of these microorganisms to the anode and cathode, and the impact on cathodic protection efficiency. The results indicate that in a marine environment containing IOB and SRB, the cathodic protection efficiency of the ICCP system increases with the negative shift of the protection potential. A more positive cathodic protection potential promotes the adhesion of mixed bacteria on the electrode surface and the formation of a biofilm, which reduces cathodic protection efficiency. In contrast, at a cathodic protection potential of −1.05 V (SCE), bacterial growth is inhibited, and a dense crystalline corrosion film primarily composed of Fe2O3 and Fe(OH)3 forms on the cathode surface. This film effectively protects the cathodic metal, significantly mitigating MIC. Full article
(This article belongs to the Section Electrochemistry and Photoredox Processes)
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19 pages, 2471 KiB  
Article
Thiol-Epoxy Click Chemistry: The Synthesis of Vicinal Amino Alcohols Containing a 1,2,4-Triazole Ring
by Artyom V. Petrosyan, Astghik A. Shahkhatuni, Andranik M. Davinyan, Karine S. Avetisyan, Tariel V. Ghochikyan, Melanya A. Samvelyan, Valentine G. Nenajdenko and Armen S. Galstyan
Chemistry 2025, 7(2), 53; https://doi.org/10.3390/chemistry7020053 - 1 Apr 2025
Viewed by 884
Abstract
As examples of “Click Chemistry”, the reaction of 1-(oxiran-2-ylmethyl)piperidine with several 1,2,4-triazoles derivatives was studied. As a result, the reaction shows that the oxirane ring opens regiospecifically, according to Krasusky’s rule, without using a catalyst. The basic nitrogen present in 1-(oxiran-2-ylmethyl)piperidine has a [...] Read more.
As examples of “Click Chemistry”, the reaction of 1-(oxiran-2-ylmethyl)piperidine with several 1,2,4-triazoles derivatives was studied. As a result, the reaction shows that the oxirane ring opens regiospecifically, according to Krasusky’s rule, without using a catalyst. The basic nitrogen present in 1-(oxiran-2-ylmethyl)piperidine has a catalytic (anchimer) effect. Full article
(This article belongs to the Special Issue Celebrating the 50th Anniversary of Professor Valentine Ananikov)
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10 pages, 1146 KiB  
Article
Effect of Gamma Irradiation on Free Radicals and the Antioxidant Properties of Walnuts
by Katerina Aleksieva, Ralitsa Mladenova, Sabina Taneva, Petko Denev and Yordanka Karakirova
Chemistry 2025, 7(2), 52; https://doi.org/10.3390/chemistry7020052 - 1 Apr 2025
Viewed by 185
Abstract
The present work represented results from a comprehensive study of free radicals and the antioxidant properties of irradiated walnuts. The effects of gamma irradiation on free radical generation and their stability, as well as on the antioxidant activity in walnuts, were investigated by [...] Read more.
The present work represented results from a comprehensive study of free radicals and the antioxidant properties of irradiated walnuts. The effects of gamma irradiation on free radical generation and their stability, as well as on the antioxidant activity in walnuts, were investigated by Electron Paramagnetic Resonance (EPR) spectroscopy, Oxygen Radical Absorbance Capacity (ORAC), and Hydroxyl Radical Antioxidant Capacity (HORAC) assays. Walnut samples were irradiated using 60Co at two different doses: 10 and 25 kGy. As a marker for the identification of high-energy radiation treatment, characteristic cellulose radical signals were detected after irradiation and remained observable for over eight months. A significant increase in antioxidant activity was observed at higher irradiation doses, as measured by DPPH free radical scavenging activity, ORAC and HORAC assays. Full article
(This article belongs to the Section Molecular Organics)
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17 pages, 3000 KiB  
Article
Tetraanion of Tetracyclopentatetraphenylene Derivative: Global Versus Local Conjugation Modes
by Hirokazu Miyoshi, Ryosuke Sugiura, Ryohei Kishi, Atsuya Muranaka, Masanobu Uchiyama, Nagao Kobayashi, Yutaka Ie, Masayoshi Nakano and Yoshito Tobe
Chemistry 2025, 7(2), 51; https://doi.org/10.3390/chemistry7020051 - 31 Mar 2025
Viewed by 252
Abstract
Multiple reduced π-conjugated hydrocarbons exhibit π-electron conjugation modes different from neutral species due to the distinct number of electrons. Herein, we report the generation of a 32 π-electron tetraanion of a derivative of a doubly cyclic π-conjugated system with 28 π-electrons, tetracyclopentatetraphenylene (TCPTP), [...] Read more.
Multiple reduced π-conjugated hydrocarbons exhibit π-electron conjugation modes different from neutral species due to the distinct number of electrons. Herein, we report the generation of a 32 π-electron tetraanion of a derivative of a doubly cyclic π-conjugated system with 28 π-electrons, tetracyclopentatetraphenylene (TCPTP), through an exhaustive reduction with potassium. Although aggregation causes some complications, based on spectroscopic and theoretical investigations, it is revealed that negative charges are located at the outer and inner peripheries, suggesting that the tetraanion adopts a globally delocalized double annulenoid (annulene-within-an-annulene, AWA) mode, with 22 π-electron outer and 10 π-electron inner aromatic perimeters. On the other hand, excess charges of the outer perimeter are mainly located at the apical position of the pentagonal rings, indicating a significant contribution of the cyclopentadienide form. The theoretical analysis of magnetically induced ring current tropicities reveals counter-rotating ring currents at the outer and inner rings, supporting the predominant contribution of the cyclopentadienide form. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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10 pages, 1536 KiB  
Communication
Metal-Free Synthesis of Benzimidazolinones via Oxidative Cyclization Under Hypervalent Iodine Catalysis
by Mayu Hirashima, Syotaro Hamatani, Hirotaka Sasa, Naoko Takenaga, Tomonori Hanasaki and Toshifumi Dohi
Chemistry 2025, 7(2), 50; https://doi.org/10.3390/chemistry7020050 - 31 Mar 2025
Viewed by 224
Abstract
Benzimidazolinones exhibit unique biological activities and serve as building blocks in synthesizing pharmaceutical compounds. Although multiple synthetic approaches involving intermolecular cyclization reactions have been reported, intramolecular cyclization reactions are scarce, and more rational synthetic methods are required. Hypervalent iodine-catalyzed oxidative C–N coupling is [...] Read more.
Benzimidazolinones exhibit unique biological activities and serve as building blocks in synthesizing pharmaceutical compounds. Although multiple synthetic approaches involving intermolecular cyclization reactions have been reported, intramolecular cyclization reactions are scarce, and more rational synthetic methods are required. Hypervalent iodine-catalyzed oxidative C–N coupling is a potentially effective approach for synthesizing benzimidazolinones under metal-free conditions. In this study, we present a method utilizing hypervalent iodine catalysis for the oxidative cyclization of N’-aryl urea compounds, resulting in the first metal-free synthesis of various benzimidazolinones. Full article
(This article belongs to the Section Molecular Organics)
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14 pages, 7373 KiB  
Article
Ultrasound-Assisted Synthesis of Microcrystalline Lanthanide Terephthalates: Insights into Morphology and Structural Properties
by Yulia N. Toikka, Polina B. Guseva, Nikita A. Bogachev, Stefaniia S. Kolesnik, Nikita A. Glukhoedov, Sergey N. Orlov, Mikhail N. Ryazantsev, Mikhail Yu. Skripkin and Andrey S. Mereshchenko
Chemistry 2025, 7(2), 49; https://doi.org/10.3390/chemistry7020049 - 28 Mar 2025
Viewed by 287
Abstract
Crystalline lanthanide terephthalates, Ln2bdc3‧nH2O (Ln = La–Lu, excluding Pm), were synthesized using a surfactant-free, ultrasound-assisted method. This approach yielded microcrystals with diverse shapes and sizes ranging from 2 to 10 μm. Notably, under these conditions, lutetium terephthalate [...] Read more.
Crystalline lanthanide terephthalates, Ln2bdc3‧nH2O (Ln = La–Lu, excluding Pm), were synthesized using a surfactant-free, ultrasound-assisted method. This approach yielded microcrystals with diverse shapes and sizes ranging from 2 to 10 μm. Notably, under these conditions, lutetium terephthalate uniquely crystallized as Lu2(1,4-bdc)3·2.5H2O, while the remaining lanthanides formed tetrahydrate terephthalates, Ln2bdc3‧4H2O (Ln = La–Nd, Sm–Yb). Full article
(This article belongs to the Section Inorganic and Solid State Chemistry)
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14 pages, 3283 KiB  
Article
A Post-Synthetic Modification Approach to Expand MIL-101-NH2 Functionalization
by Alain Vigroux, Christian Lherbet, Isabelle Fabing, Marie-Claire Barthélémy, Christophe Laurent and Pascal Hoffmann
Chemistry 2025, 7(2), 48; https://doi.org/10.3390/chemistry7020048 - 28 Mar 2025
Viewed by 237
Abstract
Considering the importance of organic functionalization of MOFs, we here report a simple, tunable and efficient one-step post-modification procedure for introducing amino and carboxylic groups into the mesoporous metal–organic framework Al- and Cr-MIL-101-NH2 based on its reaction with alkyl bromides. This procedure [...] Read more.
Considering the importance of organic functionalization of MOFs, we here report a simple, tunable and efficient one-step post-modification procedure for introducing amino and carboxylic groups into the mesoporous metal–organic framework Al- and Cr-MIL-101-NH2 based on its reaction with alkyl bromides. This procedure allows also access to polyfunctionalized MIL-101 decorated with both carboxylic and primary amino groups. Other chemical functions, such as alcohols and alkynes, were also successfully introduced by this method. Full article
(This article belongs to the Section Chemistry of Materials)
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16 pages, 2781 KiB  
Article
Tuning Low-Lying Excited States and Optical Properties in IndenoFluorene Diradicaloids and Longitudinally Extended Derivatives: A Computational Perspective
by Michele Orza, Andrea Zerbini and Fabrizia Negri
Chemistry 2025, 7(2), 47; https://doi.org/10.3390/chemistry7020047 - 19 Mar 2025
Viewed by 317
Abstract
In this work, we have considered the family of indenofluorene (IF) and its longitudinally elongated variants fluorenofluorene and diindenoanthracene and investigated their low-lying excited states and optical properties via quantum-chemical studies at the density functional theory (DFT) level. Singlet ground-state diradicals exhibit distinct [...] Read more.
In this work, we have considered the family of indenofluorene (IF) and its longitudinally elongated variants fluorenofluorene and diindenoanthracene and investigated their low-lying excited states and optical properties via quantum-chemical studies at the density functional theory (DFT) level. Singlet ground-state diradicals exhibit distinct optical properties due to the presence of a low-lying state dominated by a doubly excited configuration (DE state), often below the lowest allowed singly excited state (SE state). IFs and their elongated derivatives, with tunable diradical character and both symmetric and nonsymmetric structures, provide an ideal platform for exploring DE state energy modulation and spectroscopic behavior. The study shows that absorption spectra simulated using time-dependent (TD) calculations based on unrestricted broken-symmetry antiparallel-spin reference configuration (TDUDFT) closely match the available experimental data. Additionally, it reveals distinct spectral behavior for symmetric and nonsymmetric derivatives, highlighting the role of lowest-lying weakly allowed excited states potentially promoting non-radiative deactivation pathways. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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18 pages, 1432 KiB  
Article
Fragmentation-Based Linear-Scaling Method for Strongly Correlated Systems: Divide-and-Conquer Hartree–Fock–Bogoliubov Method, Its Energy Gradient, and Applications to Graphene Nano-Ribbon Systems
by Masato Kobayashi, Ryosuke Kodama, Tomoko Akama and Tetsuya Taketsugu
Chemistry 2025, 7(2), 46; https://doi.org/10.3390/chemistry7020046 - 18 Mar 2025
Viewed by 448
Abstract
This study introduces a fragmentation-based linear-scaling method for strongly correlated systems, specifically the divide-and-conquer Hartree–Fock–Bogoliubov (DC-HFB) approach. Two energy gradient formulations of the DC-HFB method are derived and implemented, enabling efficient optimization of molecular geometries in large systems. This method is applied to [...] Read more.
This study introduces a fragmentation-based linear-scaling method for strongly correlated systems, specifically the divide-and-conquer Hartree–Fock–Bogoliubov (DC-HFB) approach. Two energy gradient formulations of the DC-HFB method are derived and implemented, enabling efficient optimization of molecular geometries in large systems. This method is applied to graphene nanoribbons (GNRs) to explore their geometries and polyradical characters. Numerical results demonstrate that the present DC-HFB method has the potential to treat the static electron correlation and predict diradical character in GNRs, offering new avenues for studying large-scale strongly correlated systems. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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11 pages, 21344 KiB  
Article
Fully Conjugated Heteroatomic Non- and Quasi-Alternant Polyradicals
by Sergi Betkhoshvili, Jordi Poater, Ibério de P. R. Moreira and Josep Maria Bofill
Chemistry 2025, 7(2), 45; https://doi.org/10.3390/chemistry7020045 - 18 Mar 2025
Viewed by 406
Abstract
In this work, we present fully π-conjugated diradical(oid)s and tetraradical(oid)s with five-membered non-alternant cyclopentadienyl and quasi-alternant thiophene rings, the latter of which is used as a source of aromatic stabilization. By controlling the topology of the π-systems, we can restrict the [...] Read more.
In this work, we present fully π-conjugated diradical(oid)s and tetraradical(oid)s with five-membered non-alternant cyclopentadienyl and quasi-alternant thiophene rings, the latter of which is used as a source of aromatic stabilization. By controlling the topology of the π-systems, we can restrict the lower-bound number of unpaired electrons. Aromaticity and/or antiaromaticity in the different configurations of the compounds can be used to design conjugated compounds with high open-shell characters. We also designed the diradical(oid) based only on the five-membered rings, without any terminal radical groups. This work exemplifies the application of our theory of rational design of polyradicals to heteroatomic and non/quasi-alternant organic systems. The ability to create polyradicals with different classes of organic compounds establishes the possibility of creating multifunctional organic materials with tunable magnetic properties. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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12 pages, 1375 KiB  
Article
An Electronic Structural Analysis of O2-Binding Dicopper Complex: Insights from Spin Magnetism and Molecular Orbitals
by Ryusei Morimoto, Kanami Sugiyama, Masahiro Higashi and Hirofumi Sato
Chemistry 2025, 7(2), 44; https://doi.org/10.3390/chemistry7020044 - 18 Mar 2025
Viewed by 325
Abstract
We investigated the geometry and electronic structure of the oxygen-bridged dicopper complex [CuII2(NH3)4O2]2+ and discussed how different DFT methods and basis sets, including dispersion corrections and dielectric media, affect the predicted structure and [...] Read more.
We investigated the geometry and electronic structure of the oxygen-bridged dicopper complex [CuII2(NH3)4O2]2+ and discussed how different DFT methods and basis sets, including dispersion corrections and dielectric media, affect the predicted structure and spin state. Our results showed that pure functionals yielded the closed-shell singlet character, whereas hybrid functionals presented a partial diradical character that coincided with increased spin contamination. Incorporating a polarizable continuum model further enhanced the diradical character and more closely reproduced the measured Cu–Cu distance with a bent Cu2O2 core. Analysis of the molecular orbitals and computed absorption spectra revealed how orbitals produce the key transition from ligand-to-metal charge transfer. These findings underscore how environmental effects influence the description of Cu2O2 chemistry. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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25 pages, 12645 KiB  
Article
Molecular Iodine-Catalyzed Synthesis of 3,3-Disubstituted Isatins: Total Synthesis of Indole Alkaloid, 3,3-Dimethoxy-2-oxindole
by Keisuke Tokushige, Shota Asai and Takumi Abe
Chemistry 2025, 7(2), 43; https://doi.org/10.3390/chemistry7020043 - 17 Mar 2025
Viewed by 425
Abstract
3,3-Dialkoxy-2-oxindoles are prevalent in natural products and exhibit unique biological activities. Among them, acyclic alkoxy analogues show instability in acidic conditions, making access to acyclic isatin ketals highly challenging. Conventional methods for the synthesis of 3,3-dialkoxy-2-oxindoles usually require strongly acidic and harsh reaction [...] Read more.
3,3-Dialkoxy-2-oxindoles are prevalent in natural products and exhibit unique biological activities. Among them, acyclic alkoxy analogues show instability in acidic conditions, making access to acyclic isatin ketals highly challenging. Conventional methods for the synthesis of 3,3-dialkoxy-2-oxindoles usually require strongly acidic and harsh reaction conditions, resulting in a low overall efficiency. Herein, we report on an acid- and metal-free protocol for the synthesis of 3,3-dialkoxy-2-oxindoles from isatins through an iodine-catalyzed ketalization. This photochemical protocol does not require the use of any specific reagents such as metal catalysts. Furthermore, the total synthesis of an unprecedented 2-oxindole alkaloid bearing 3,3-dimethoxy moiety is achieved. Full article
(This article belongs to the Section Molecular Organics)
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14 pages, 1701 KiB  
Article
Citric Acid-Catalyzed Three-Component Synthesis of (E)-3-Aryl-2-styryl-2,3-dihydroquinazoline-4(1H)-ones and Their Mild Oxidation with I2/DMSO System into (E)-3-Aryl-2-styrylquinazolin-4(3H)-ones
by Vladimir V. Kouznetsov, Angélica Peñaranda Gómez and Carlos E. Puerto Galvis
Chemistry 2025, 7(2), 42; https://doi.org/10.3390/chemistry7020042 - 16 Mar 2025
Viewed by 329
Abstract
We hereby report a simple and efficient method for the preparation of (E)-3-aryl-2-styryl-2,3-dihydroquinazolin-4-(1H)-ones, from isatoic anhydride, anilines, and cinnamaldehydes in the presence of 20 mol% citric acid in methanol at 60 °C for 2 h. The styryl-dihydroquinazolin-4-(1H)-one [...] Read more.
We hereby report a simple and efficient method for the preparation of (E)-3-aryl-2-styryl-2,3-dihydroquinazolin-4-(1H)-ones, from isatoic anhydride, anilines, and cinnamaldehydes in the presence of 20 mol% citric acid in methanol at 60 °C for 2 h. The styryl-dihydroquinazolin-4-(1H)-one products were obtained in moderate and good yields (30–80%) through the three-component condensation reaction, under an environment-friendly protocol. The latter were easily transformed into styrylquinazolin-4-(3H)-one derivatives with 57–91% yields using a mild oxidation with an I2/DMSO system for less than 60 min. Full article
(This article belongs to the Section Molecular Organics)
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15 pages, 4074 KiB  
Article
Synthesis and Anticancer Activity of Bis(2-picolyl)amine Derivatives with a Biaryl Moiety as a Photosensitizer
by Yoshimi Ichimaru, Koichi Kato, Koushirou Sogawa, Daichi Egawa, Hideaki Kato, Kazuaki Katakawa, Wanchun Jin, Masaaki Kurihara and Hiromasa Kurosaki
Chemistry 2025, 7(2), 41; https://doi.org/10.3390/chemistry7020041 - 15 Mar 2025
Viewed by 363
Abstract
Metal complexes have potential applications in drug discovery due to their unique properties. For example, zinc(II) ions (ZnII) exhibit a high affinity for DNA and have been used as active centers in artificial protein/small-molecule metallonucleases. In this study, we designed a [...] Read more.
Metal complexes have potential applications in drug discovery due to their unique properties. For example, zinc(II) ions (ZnII) exhibit a high affinity for DNA and have been used as active centers in artificial protein/small-molecule metallonucleases. In this study, we designed a series of ligands containing a biaryl moiety as a photosensitizer to synthesize ZnII complexes with enhanced DNA affinity for use as DNA photocleavage reagents. The DNA photocleavage activity of these complexes was evaluated using the pUC19 plasmid, revealing that the ZnII complex bearing the 4′-biphenyl-bpa (bpa = bis(2-picolyl)amine) ligand L1 exhibited the strongest DNA photocleavage activity. Further analysis of the biological activity of the ZnII complex of L1 in the human pancreatic cancer cell line MIA PaCa-II demonstrated that its cytotoxic activity increased in a UV irradiation time-dependent manner, with an IC50 value of 14.2 μM. Fluorescence staining revealed that the ZnII complex of L1 generates reactive oxygen species in cells, leading to DNA double-strand breaks upon UV irradiation and ultimately resulting in necrotic cell death. These findings highlight the potential of the ZnII complex of L1 as a photochemotherapeutic agent for pancreatic cancer. Full article
(This article belongs to the Section Medicinal Chemistry)
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16 pages, 6576 KiB  
Review
m-Quinodimethane-Based Fused-Ring Diradicals with Singlet and Triplet Ground States
by Akihiro Shimizu
Chemistry 2025, 7(2), 40; https://doi.org/10.3390/chemistry7020040 - 13 Mar 2025
Viewed by 383
Abstract
Diradicals have attracted the attention of chemists due to their unique electronic structures and properties originating from unpaired electrons. One of the fundamental motifs of diradicals is quinodimethane; p- and o-quinodimethanes are singlet Kekulé hydrocarbons, while m-quinodimethane is a triplet [...] Read more.
Diradicals have attracted the attention of chemists due to their unique electronic structures and properties originating from unpaired electrons. One of the fundamental motifs of diradicals is quinodimethane; p- and o-quinodimethanes are singlet Kekulé hydrocarbons, while m-quinodimethane is a triplet non-Kekulé hydrocarbon. Most of the hydrocarbon diradicals studied to date have been limited to p- and o-quinodimethane-based non-fused-ring and fused-ring open-shell singlet diradicals and m-quinodimethane-based non-fused-ring triplet diradicals. In this account, studies on m-quinodimethane-based fused-ring diradicals, including an open-shell singlet Kekulé hydrocarbon, an open-shell singlet zwitterion, non-Kekulé hydrocarbon-based triplet diradical and diradical cation, and a triplet Kekulé hydrocarbon, are summarized. They are designed, successfully synthesized, and isolated as crystals, and their fundamental electronic structures and properties have been elucidated by optical, electrochemical, and magnetic measurements, together with DFT calculations. A series of studies showed that controlling the interaction between the two unpaired electrons of m-quinodimethane through an appropriate molecular design would produce polycyclic diradicals with various open-shell singlet diradical characters and the energy differences between singlet and triplet states. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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10 pages, 2571 KiB  
Article
2,4,6-Trichlorophenyl-Substituted [3]Triangulene with Enhanced Stability
by Yiming Yang, Peipei Liu, Xiaoli Zhao and Xueliang Shi
Chemistry 2025, 7(2), 39; https://doi.org/10.3390/chemistry7020039 - 13 Mar 2025
Viewed by 644
Abstract
Triangulene, also known as Clar’s hydrocarbon, has been sought after by chemists for more than 70 years but with limited success. Herein, we report an oxidative dehydrogenation method to synthesize two kinetically blocked [3]triangulene derivatives TRI-1 (reported) and TRI-2 (newly synthesized), in which [...] Read more.
Triangulene, also known as Clar’s hydrocarbon, has been sought after by chemists for more than 70 years but with limited success. Herein, we report an oxidative dehydrogenation method to synthesize two kinetically blocked [3]triangulene derivatives TRI-1 (reported) and TRI-2 (newly synthesized), in which the three most reactive sites are substituted by bulky mesityl groups and electron-withdrawing 2,4,6-trichlorophenyl groups, and meanwhile, three vertices of triangulene are substituted by tert-butyl groups. Interestingly, the dihydro-triangulene core possesses two isomers well characterized by UV-vis, NMR spectroscopy, and X-ray crystallographic analysis, which is interestingly substituent-dependent. The newly synthesized TRI-2 is isolated in crystalline form, and X-ray crystallographic analysis reveals that the aryl substituents are nearly perpendicular to the triangulene plane and thus cause little perturbation of the electronic properties of the triangulene. Notably, 2,4,6-trichlorophenyl-substituted TRI-2 exhibits enhanced stability compared to the reported mesityl-substituted TRI-1, e.g., TRI-2 is stable for months in a crystalline state under a nitrogen atmosphere, and TRI-2 in a solution state is also more persistent than TRI-1 (half-life for TRI-1 ≈ 18 h vs. TRI-2 ≈ 132 h). This achievement will facilitate the design and synthesis of stable triangulene dimers and oligomers with higher spin multiplicity. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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69 pages, 11327 KiB  
Review
Quantum Mechanical Approaches to Strongly Correlated Electron Systems: Structure, Bonding, and Properties of Diradicals, Triradicals, and Polyradicals
by Satoru Yamada, Isamu Shigemoto, Takashi Kawakami, Hiroshi Isobe, Mitsuo Shoji, Koichi Miyagawa and Kizashi Yamaguchi
Chemistry 2025, 7(2), 38; https://doi.org/10.3390/chemistry7020038 - 12 Mar 2025
Viewed by 720
Abstract
The structure, bonding, and properties of diradicals, triradicals, and polyradicals have been investigated using broken symmetry (BS) molecular orbital (MO) and BS density functional theory (DFT) methods, which are regarded as the first steps in the mean-field approach toward strongly correlated electron systems [...] Read more.
The structure, bonding, and properties of diradicals, triradicals, and polyradicals have been investigated using broken symmetry (BS) molecular orbital (MO) and BS density functional theory (DFT) methods, which are regarded as the first steps in the mean-field approach toward strongly correlated electron systems (SCES). The natural orbital (NO) analyses of the BS MO and BS DFT solutions were performed to elucidate the natural orbitals of their occupation numbers, which are used for derivations of the diradical character (y) and several chemical indices for the open-shell molecules under investigation. These chemical indices are also obtained using SCES, the next theoretical step, which uses symmetry-recovered resonating BS (RBS) and multi-determinant methods such as multi-reference (MR) configuration interaction (CI) and MR-coupled cluster (CC) methods that employ the NOs generated in the first step. The nonlinear optical response properties of organic open-shell species were theoretically investigated with several procedures, such as MR CI (CC), the numerical Liouville, and Monte Carlo wavefunction methods, as the third step to SCES. The second-order hyperpolarizability (γ) of diradicals such as a phenalenyl radical dimer were mainly investigated in relation to the generation of quantum squeezed lights, which are used for the construction of the quantum entangled states for quantum optical devices such as quantum sensing and quantum computation. Basic quantum mechanical concepts, such as the Pegg–Barnett quantum phase operator, were also revisited in relation to the design and chemical synthesis of stable diradicals and polyradicals such as optical quantum molecular materials and future molecular qubits materials. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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13 pages, 4415 KiB  
Article
A Stable π-Expanded o-Quinodimethane via the Photochemical Dearomative Cycloaddition of Corannulene with an Isolable Dialkylsilylene
by Shintaro Ishida, Maiko Mori, Shunya Honda and Takeaki Iwamoto
Chemistry 2025, 7(2), 37; https://doi.org/10.3390/chemistry7020037 - 11 Mar 2025
Viewed by 617
Abstract
A stable π-expanded o-quinodimethane derivative (2) was synthesized by photochemical dearomative cycloaddition of corannulene with an isolable dialkylsilylene (1) and isolated as a dark blue solid. Compound 2 adopts a very flat bowl shape in contrast to parent [...] Read more.
A stable π-expanded o-quinodimethane derivative (2) was synthesized by photochemical dearomative cycloaddition of corannulene with an isolable dialkylsilylene (1) and isolated as a dark blue solid. Compound 2 adopts a very flat bowl shape in contrast to parent corannulene. Structural and spectroscopic characteristics, redox properties, and computational study suggest that 2 has a small but significant diradical character (y0 = 0.11). One-electron reduction of 2 provides the corresponding radical anion as an isolable salt. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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27 pages, 7757 KiB  
Article
New Derivatives of Oleanolic Acid: Semi-Synthesis and Evaluation of Their Anti-15-LOX, Anti-α-Glucosidase and Anticancer Activities and Molecular Docking Studies
by Nahla Triaa, Salma Jlizi, Mansour Znati, Hichem Ben Jannet and Jalloul Bouajila
Chemistry 2025, 7(2), 36; https://doi.org/10.3390/chemistry7020036 - 7 Mar 2025
Viewed by 595
Abstract
A novel series of oleanolic acid (OA, 1) derivatives incorporating phenolic and coumarin moieties were synthesized. This acid was extracted from olive pomace (Olea europaea L.) using an ultrasound-assisted method. The structures of these novel derivatives of OA were [...] Read more.
A novel series of oleanolic acid (OA, 1) derivatives incorporating phenolic and coumarin moieties were synthesized. This acid was extracted from olive pomace (Olea europaea L.) using an ultrasound-assisted method. The structures of these novel derivatives of OA were characterized through the utilization of 1H-NMR, 13C-NMR and ESI-HRMS analyses. An evaluation of some biological activities of the prepared derivatives was conducted. The evaluation focused principally on the capacity of these structures to inhibit 15-lipoxygenase and α-glucosidase, as well as their anticancer properties when tested against tumour cell lines (HCT-116 and LS-174T) and a non-tumour cell line (HEK-293). In terms of their cytotoxic activity, the majority of the compounds exhibited notable inhibitory effects compared to the starting molecule, OA. Derivatives 4d, 4k and 4m exhibited particularly strong inhibitory effects against the HCT-116 cell line, with IC₅₀ values of 38.5, 39.3, 40.0 µM, respectively. Derivatives 4l, 4e and 5d demonstrated the most effective inhibition against the LS-174T cell line, with IC50 values of 44.0, 44.3, 38.0 µM, respectively. However, compound 2a was the most effective, exhibiting the most potent inhibition of 15-lipoxygenase and α-glucosidase, with IC₅₀ values of 52.4 and 59.5 µM, respectively. Furthermore, molecular docking studies supported in vitro cytotoxic activity, revealing that the most potent compounds exhibited low binding energies and interacted effectively within the EGFR enzyme’s active pocket (PDB: 1M17). These findings highlight the potential of these derivatives as anticancer agents and enzymatic inhibitors, warranting further investigation. Full article
(This article belongs to the Section Medicinal Chemistry)
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