Chemistry

Long-range proton transfer in several conjugated proton cranes, originating from 7-hydroxy quinoline as a proton transfer platform, has been investigated theoretically by means of DFT and TD-DFT methodology. Major emphasis was given to their applicability to provide clean switching upon irradiation. The border conditions require the existence of a single enol tautomer in the ground state, which under excitation through a series of consecutive exited and ground state intramolecular proton transfer steps is transferred to the keto tautomer. It was shown that the most suitable candidates are based on using iso-quinoline, pyrimidine and 4-nitropyridine as proton crane units. Their suitability is a function of aromaticity changes, the basicity of the nitrogen atom from the proton crane unit and the structural effects originating from their conjugation with 7-hydroxy quinoline. Full article

The alkoxycarbonylation of styrene by palladium chloride is studied employing the density functional theory (DFT). Initially, [PdCl₃]^– reacts with methanol to form the methoxy-bound intermediate, which undergoes β-hydride elimination to form the key intermediate [PdCl₂H]^–. Then, a 1,2-insertion reaction to styrene takes place to form linear and branched alkyl coordinated with the Pd^II. Then, CO coordination followed by a 1,1-insertion reaction leads to the formation of acyl intermediate. Next, the methanolysis leads to the formation of esters. Previous reports with other catalysts suggested the intermolecular/intramolecular transition state (TS) formation with a high activation barrier, and this step was the bottleneck. To the best of our knowledge, this is the first time we have considered a two-step mechanism for the alcoholysis of the ester formation mechanism. After coordination with the metal, the methanol undergoes oxidative addition to form the Pd^IV square pyramidal intermediate, followed by reductive elimination to form the ester with regeneration of the metal hydride active intermediate. Deeper insight into the nature of bonding at the TSs is obtained through energy decomposition with natural orbital for chemical valence (EDA-NOCV) and quantum theory of atoms in molecules (QTAIM). Full article

Diradical character is one of the characteristic quantities of functional open-shell molecules. Prof. Nakano devotedly studied the relationship between diradical character and material properties of open-shell molecules; now, we can use the diradical character as a powerful tool for molecular material designs. It is still unclear how the open-shell molecules are affected by the interaction with the surface although the molecules have been immobilised for device applications. In the present study, the adsorptions of model diradical molecules with s-electrons on the MgO (001) and BaO (001) surfaces are investigated using approximate spin projected density functional theory with plane-wave basis (AP-DFT/plane-wave) to provide a systematic discussion of surface–diradical interactions. The accuracy of AP-DFT/plane-wave was verified by comparisons with the calculated results by NEVPT2. The computational error introduced by DFT calculations on the diradical state (spin contamination error) is reduced by the surface–diradical interaction. In addition, it is shown that (1) the diradical character is amplified by the orbital polarisation effects of oxide ions, and (2) the character decreases when the magnetic orbitals become electron-rich due to electron donation from the surfaces. The two effects are competing; the former is pronounced in Au systems, whereas the latter is pronounced in Ag systems. Full article

Imidazolium-based ionic liquids (ILs) have been regarded as green solvents owing to their unique properties. Among these, the melting point is key to their excellent performance in applications such as catalysis, biomass processing, and energy storage, where stability and operational temperature range are critical. The utilization of neural networks for forecasting the melting point is highly significant. Nevertheless, the excessive selection of descriptors obtained by density functional theory (DFT) calculations always leads to huge computational costs. Herein, this study strategically selected only 12 kinds of quantum chemical descriptors by employing a much more efficient semi-empirical method (PM7) to reduce computational costs. Four principles of data pre-processing were proposed, and the innovative use of a simulated annealing algorithm to search for the lowest energy molecular conformation improved accuracy. Based on these descriptors, a multi-layer perceptron neural network model was constructed to efficiently predict the melting points of 280 imidazolium-based ILs. The R² value of the current model reached 0.75, and the mean absolute error reached 25.03 K, indicating that this study achieved high accuracy with very little computational cost. This study reveals a strong correlation between descriptors and melting points. Additionally, the model accurately predicts unknown melting points of imidazolium-based ILs, achieving good results efficiently. Full article

Three new acylated benzophenone O-glycosides named aucherosides A–C (4–6), together with five known compounds such as mangiferin (1), maclurin-6-O-β-D-glucopyranoside (2), 1-O-galloyl-β-D-glucose (3), vanillic acid (7), and 5-hydroxy-2-isopropylchromone-7-O-β-glucoside (8), were isolated from the aerial parts of Hypericum aucheri Jaub. and Spach and identified with spectroscopic methods (1D and 2D NMR, and HRESIMS). Compounds 2, 4–6, 8, and previously isolated from the title plant aucherines A–C (9–11), were tested for hMAO-A and B inhibitory effects and neuroprotection. All tested compounds (1 µM) did not exhibit any inhibitory effect on hMAO-A and showed significant inhibitory activity against the hMAO-B enzyme. Notably, compound 8 demonstrated the strongest hMAO-B inhibition, approaching that of the positive control selegiline. At high concentrations (100 µM), all tested compounds showed no neurotoxic or pro-oxidant effects on rat brain synaptosomes, mitochondria, and microsomes. All tested compounds exhibited good neuroprotective and antioxidant activities in various neurotoxicity models (6-hydroxydopamine-induced neurotoxicity on synaptosomes, tert-butyl hydroperoxide-induced oxidative stress on mitochondria, and non-enzymatic lipid peroxidation on microsomes). The neuroprotective mechanisms of these compounds may include MAO-B inhibition, reactive oxygen species (ROS) scavenging, membrane stabilization, and preservation of reduced glutathione (GSH), the primary nucleophilic ROS scavenger. Full article

Hydrotalcite-like materials (OSA-LDH) were prepared used oil shale ash (OSA), which came from a thermal power plant area, as the main raw material. The characterization results of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and thermogravimetric-differential scanning calorimetry (TG-DSC) showed that the prepared samples were mesoporous materials in a crystal state and were layered and contained lattice oxygen and a large number of surface hydroxyl groups. The adsorption property of the prepared samples was confirmed and evaluated by adsorption experiments with Pb²⁺ as the target pollutant. The adsorption process was in accord with the Langmuir isothermal adsorption equation, and the adsorption data fitted perfectly with the pseudo-second kinetic equation. The saturated adsorption capacity for Pb²⁺ was 120.92 mg·g⁻¹ at a temperature of 298 K and initial concentration of 300 mg·L⁻¹. The main adsorption mechanisms of OSA-LDH for Pb²⁺ were chemical bond cooperation and electrostatic bond cooperation. This paper aimed to not only prepare an economical and effective adsorbent to remove heavy metal ions from the solution but also provide a new path for the treatment and utilization of OSA so as to realize efficient waste resource utilization. Full article

Chiral electroactive materials have attracted attention for the effects of electrical magnetochiral anisotropy (eMChA) and chirality-induced spin selectivity (CISS). The combination of tetrathiafulvalene (TTF) with chiral moieties is one way to access chiral electroactive materials. In this paper, we have focused on the fused 2,3-dimethylcyclohexene (DMCh) ring as a substituent with chiral carbon atoms and without heteroatoms, which has not been used in the field of molecular conductors, and we synthesized a new TTF derivative (rac-DMCh-EDT-TTF). We have developed novel molecular conductors (rac-DMCh-EDT-TTF)₂X (X⁻ = PF₆⁻, AsF₆⁻ and ClO₄⁻), which have bilayer conducting sheets composed of the two crystallographically independent molecules. All salts exhibited semiconducting behavior from room temperature down to low temperatures, and a resistivity anomaly was observed at 180–250 K. X-ray structure analysis at 100 K and 263 K and molecular orbital calculations using the results of X-ray structure analysis indicated the emergence of a charge disproportionation between Layers 1 and 2 at the low-temperature phase. Full article

Background: Reflecting the increasing interest and research on living a healthy life as society ages, there has been a surge in attention and studies on photodamage. Probiotics have been studied for their ability to enhance skin integrity and provide protection from ultraviolet radiation (UVR). However, despite this, extensive research has revealed various issues and side effects, prompting increased interest in alternative options that can effectively and safely protect the skin. We focused on postbiotics as a promising solution for photodamage, aiming to demonstrate their potential as a safe and stable alternative to probiotics. Methods: We investigated papers on “skin aging” or “photoaging” and “probiotics” or “postbiotics” from 2013 to 2023 using the Web of Science, PubMed, and Scopus. Additionally, we compared and analyzed publications, authors, countries, keywords, and citations using the VOS viewer program. Results: According to our search results, the majority of papers on photodamage and probiotics were published in PubMed, with the United States leading in publication volume among countries. The most common keywords were “photodamage” and “skin”. The most cited paper recorded 470 citations. Furthermore, upon focused analysis of five papers on postbiotics and photodamage, postbiotics demonstrated preventive and protective effects against skin photodamage. Conclusions: Postbiotics for photodamage show potential as a safe and stable alternative to probiotics. However, research on postbiotics and photodamage remains limited, and additional studies and long-term tracking are essential to substantiate our claims. Full article

Alzheimer’s Disease (AD) is the most common form of dementia in individuals over the age of 65. There is no known prevention for the progression of the disease, although the FDA recently approved two drugs for AD. The exact etiology of AD is still under debate; however, it is commonly associated with the aggregation of amyloid-beta (Aβ) plaques in the brain. Recently some extended chalcones were reported to be potential anti-amyloidogenic agents. In this study, a larger library of extended chalcone analogs were synthesized with modifications on both rings. These were tested using the Thioflavin T fluorescence assay to measure their anti-Aβ aggregation properties. Three notably active compounds were further evaluated for potential neurotoxicity and neuroprotection using an MTT cell viability assay. These compounds were non-neurotoxic and displayed a trend toward neuroprotection. These were further assessed in a Drosophila melanogaster animal AD model. A forced climbing assay revealed statistically significant changes in flies’ movement by ~30% when fed these anti-amyloidogenic agents. Full article

Since the emergence of microfluidic devices, subtractive manufacturing techniques have dominated their production. Although the conventional manufacturing processes are well established, they come along with some disadvantages that limit the accessibility and hinder the further development of microfluidics. With the rise of additive manufacturing, researchers are focused on developing alternative fabrication methods to promote affordability and accessibility. This paper presents the opportunities and challenges of laser-based stereolithography printers for the fabrication of microfluidic equipment. Emphasis is put on the design and iterative prototyping process from the initial design idea to the final device. To print with adequate and sufficient geometrical accuracy and suitable material, the optimization of the printer’s performance is discussed. Regarding the design of multiphase microfluidics and its complex fluid behavior, suitable surface treatments, including an appropriate cleaning protocol, and coating strategies to make the printed channels either hydrophilic or hydrophobic are presented to ensure applicability. With these fundamentals of additive manufacturing in microfluidic fabrication at hand, the second focus of this contribution is on the application of a modular co-flow device and a monolithic flow-focusing device to generate droplets and slugs in different multiphase flow applications. The presented co-flow setup features a tapered capillary that affects the droplet and slug sizes due to differing diameters, with larger diameters leading to larger droplets and slugs and vice versa. Several design parameters for the flow-focusing device were evaluated to determine the influence of device design on multiphase flow formation. It was found that the diameter of the inlet for the dispersed phase has the greatest effect on the size of the resulting droplets and slugs and covers the largest range of adjustable sizes. Full article

The modification of carborane anion monocarba-closo-dodecaborate (1) with perfluoroalkyl groups enhances its solubility in fluorinated ethers. This novel approach achieves a degree of solubility that is unattainable by using traditional lipophilic modifications or boro–vertex functionalizations of 1. A spectroscopic analysis in combination with DFT calculations confirmed that these new anions retain their weakly coordinating nature and exhibit moderate chemical stability. Full article

As talk grows about billions or even trillions of dollars being directed toward potential “Net Zero” activities, it is imperative that the chemistry inherent in or driving those actions make scientific sense. The challenge is to close the mass and energy balances to the carbon and oxygen cycles in the Earth’s atmosphere and oceans. Several areas of climate science have been identified that chemists can investigate through methods that do not require a supercomputer or a climate model for investigation, most notably the following: (1) The carbon cycle, which still needs to be balanced, as many known streams, such as carbon to landfills, carbon in human-enhanced sewage and land runoff streams, and carbon stored in homes and other material, do not seem to have been accounted for in carbon balances used by the IPCC. (2) Ocean chemistry and balances are required to explain the causes of regional and local-scale salinity, pH, and anoxic conditions vs. global changes. For example, local anoxic conditions are known to be impacted by changes in nutrient discharges to oceans, while large-scale human diversions of fresh water streams for irrigation, power, and industrial cooling must have regional impacts on oceanic salinity and pH. (3) Carbon Capture and Storage (CCS) schemes, if adopted on the large scales being proposed (100s to 1000s of Gt net injection by 2100), should impact the composition of the atmosphere by reducing free oxygen, adding more water from combustion, and displacing saline water from subsurface aquifers. Data indicate that atmospheric oxygen is currently dropping at about twice the rate of CO₂ concentrations increasing, which is consistent with combustion chemistry with 1.5 to 2 molecules of oxygen being converted through combustion to 1 molecule of CO₂ and 1 to 2 molecules of H₂O, with reverse reactions occurring as a result of oxygenic photosynthesis by increased plant growth. The CCS schemes will sabotage these reverse reactions of oxygenic photosynthesis by permanently sequestering the oxygen atoms in each CO₂ molecule. Full article

Effects of the number of monomers (N) on the two-photon absorption (TPA) properties of π-stacked multimer models consisting of phenalenyl radicals were investigated theoretically. We conducted spectral simulations for the π-stacked N-mer models (N = 2, 4, and 6) with different stacking distances (d₁) and their alternation patterns (d₂/d₁). Excitation energies and transition dipole moments were calculated at the extended multi-configurational quasi-degenerate second-order perturbation theory (XMC-QDPT2) level based on the complete active space self-consistent field (CASSCF) wavefunctions with the active space orbitals constructed from the singly occupied molecular orbitals (SOMOs) of monomers. The TPA cross-section value per dimer unit at the first peak, originating from the electronic transition along the stacking direction, was predicted to increase significantly as the d₂/d₁ approaches one, as the d₁ decreases, and as the N increases from 2 to 6. These tendencies are similar to the calculation results for the static hyperpolarizabilities. Full article

Traditional barcode encoding methods are constrained by the inability to dynamically control crystal orientations, thereby limiting their applications. In this work, we investigate the dynamic magnetic control of lanthanide metal–organic framework crystals and their potential for advancing photonic barcode technology. A paramagnetic fluorescent Eu-MOF microcrystal with sizes ranging from 30 to 40 μm in length and 5 to 10 μm in width was synthesized, and its magnetic orientation and polarized emission were systematically investigated. Eu-MOF crystallizes in an orthorhombic space group, growing along the crystallographic b-axis and ultimately forming an anisotropic cuboid shape. Eu-MOF microcrystals exhibit significant magnetic anisotropy, causing the crystallographic c-axis of the crystal to align with the magnetic field when a uniaxial magnetic field of ~10 mT is applied. Furthermore, the Eu-MOF microcrystal exhibited characteristic Eu emissions with peaks at 594 nm, 616 nm, and 695 nm, and showed a high degree of polarization (DOP), reaching 0.904 at 616 nm. Therefore, the utilization of a rotating magnetic field not only enables precise and dynamic control over the crystal orientations but also results in a significant variation in the luminescence intensity. This capability enabled us to propose an innovative encryption barcode scheme in which the emission intensities of different luminescence peaks are converted into barcode widths, with the sequence of magnetic field directions serving as the encryption key. This approach presents a novel method for data storage and anti-counterfeiting, significantly enhancing the versatility and capacity of photonic barcodes. Full article

New EA-sulfonamides and indazole-sulfonamides were synthesized, characterized, and evaluated for their anticancer activities. The target compound structures were elucidated using various spectroscopic techniques such as NMR-{¹H and ¹³C}, infrared spectroscopy, and high-resolution mass spectrometry. The anticancer activities of the novel compounds were evaluated against four human cancer cell lines, namely A-549, MCF-7, Hs-683, and SK-MEL-28 as well as the normal cell line HaCaT, using 5-fluorouracil and etoposide as reference drugs. Among the tested compounds, 9, 10, and 13 exhibited potent anticancer activities which are better than or similar to the reference compounds 5-fluorouracil and etoposide, against the A-549, MCF-7, and Hs-683 cancer cell lines, with IC₅₀ values ranging from 0.1 to 1 μM. Molecular docking studies of compounds 9, 10, and 13 showed a strong binding with selected protein kinase targets, which are linked to the tested cancer types. Furthermore, the analysis of the molecular dynamics simulation results demonstrated that compound 9 exhibits significant stability when bound to both JAK3 and ROCK1 kinases. This new compound has the potential to be developed as a novel therapeutic agent against various cancers. Full article

This research study computationally examined the thermal decomposition of three molecules, 3,6-dihydro-2H-pyran, 4-methyl-3,6-dihydro-2H-pyran, and 2,6-dimethyl-3,6-dihydro-2H-pyran, using the PBE0/6-311+G(d,p) level of theory and a concerted mechanism with a 6-member cyclic transition state. For this analysis, kinetic and thermodynamic parameters were calculated for reactions within a temperature range of 584 to 633 K and compared with experimental data. Our results revealed that methyl substituents at 2, 4, and 6 positions decrease the activation free energy of the molecules. Even though the evaluated reactions exhibited high absolute synchronicity, significant differences were observed regarding the extent of their bond evolution. Full article

The coordination modes of several ortho-substituted benzoates towards the copper(II) centre are investigated. The coordination environment of the metal ion includes nitrogen atoms from 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) and occasionally oxygen atoms from coordinated water, ethanol molecules, or nitrate ions. The compounds are investigated by a variety of spectroscopic methods and by single-crystal X-ray diffraction. Although the reaction scheme involved equimolar amounts of the reactants, cationic dinuclear compounds with a metal/benzoate/diimine ratio of 2:3:2 have been realized, cationic in nature regardless of the counter anion used. Furthermore, the carboxylate moieties display a range of twisting relative to the orientation of the benzene ring to which they are attached. Full article

This study successfully prepared a hierarchically porous ZIF-67 (H-ZIF-67) by incorporating the polyvinylpyrrolidone (PVP) at room temperature. Compared to standard control ZIF-67 (C-ZIF-67) with a yield of 81% and a BET specific surface area of 1228 m²·g⁻¹, the H-ZIF-67 not only exhibited improved crystallinity and pore structure but also achieved a yield of up to 93% and a BET specific surface area of 1457 m²·g⁻¹. Due to its hierarchically porous structure, H-ZIF-67 demonstrated excellent adsorption capacity and efficiency for methylene orange (MO). Additionally, the composite separator created by combining H-ZIF-67 with nanocellulose (CNF) exhibited remarkable uniformity and dispersion in zinc batteries. In comparison to a conventional CNF separator, the porous structure and high specific surface area of H-ZIF-67 significantly enhanced its electrolyte wettability and Zn²⁺ transport rates. Its abundant Lewis acid sites effectively promoted the uniform deposition of Zn²⁺, thereby suppressing the formation of zinc dendrites and improving the cycling and safety performance of zinc-ion batteries. Experimental results indicate that the ion conductivity of the membrane was 4.31 mS·cm⁻¹, the electrolyte absorption rate was 316%, and it could cycle stable for over 4000 h at a current density of 1 mA·cm⁻² with a discharge capacity of 1 mAh·cm⁻². This achievement will open up new avenues for the preparation and application of ZIF-67 composite separators in aqueous zinc-ion batteries. Full article

Sesamin, a tetrahydrofuran lignan, has gained significant attention over the past few decades due to its versatile medicinal activities. However, until now, the research on sesamin analogues has not been explored extensively. In this study, a series of new N-aryl-azasesamins were synthesized for the first time using sesamin as a raw material. The mechanism of the key breakage of the ethereal bond of the tetrahydrofuran ring in sesamin has been studied. The configuration of C6 in N-aryl-azasesamins was confirmed through NMR and X-ray single crystal refraction analyses. The results showed that the configuration of N-aryl-azasesamins was opposite to sesamin in C6. Subsequently, the N-aryl-azasesamins were evaluated for their antifungal and antitumor activities via micro-broth dilution and MTT assays. It was observed that none of the N-aryl-azasesamins exhibited inhibitory activity against the growth of C. albicans and C. neoformans at a concentration of 100 μg/mL. Most analogues showed no activity against HepG2 cells. However, 21c and 21k demonstrated antitumor activity after 24 h of incubation with IC₅₀ values of 6.49 μM and 4.73 μM, respectively. These results suggest that some N-aryl-azasesamins exhibit significantly enhanced antitumor activity compared with sesamin. Full article