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[Display omitted] • RuO 2 (1 1 0) surface is reported as an active catalyst for ethylene production from methane. • Diffusion of intermediates and ethylene desorption on RuO 2 (1 1 0) surface are facile. • The temperature of catalytic conversion of methane can be remarkably low as 200 K. • 100 % ethylene selectivity could be reached at low temperatures (300 – 450 K). Despite significant progress in low-temperature methane (CH 4) activation, commercial viability, specifically obtaining high yields of C 1 /C 2 products, remains a challenge. High desorption energy (>2 eV) and overoxidation of the target products are key limitations in CH 4 utilization. Herein, we employ first-principles density functional theory (DFT) and microkinetics simulations to investigate the CH 4 activation and the feasibility of its conversion to ethylene (C 2 H 4) on the RuO 2 (1 1 0) surface. The C H activation and CH 4 dehydrogenation processes are thoroughly investigated, with a particular focus on the diffusion of surface intermediates. The results show that the RuO 2 (1 1 0) surface exhibits high reactivity in CH 4 activation (E a = 0.60 eV), with CH 3 and CH 2 are the predominant species, and CH 2 being the most mobile intermediate on the surface. Consequently, self-coupling of CH 2 * species via C C coupling occurs more readily, yielding C 2 H 4 , a potential raw material for the chemical industry. More importantly, we demonstrate that the produced C 2 H 4 can easily desorb under mild conditions due to its low desorption energy of 0.97 eV. Microkinetic simulations based on the DFT energetics indicate that CH 4 activation can occur at temperatures below 200 K, and C 2 H 4 can be desorbed at room temperature. Further, the selectivity analysis predicts that C 2 H 4 is the major product at low temperatures (300–450 K) with 100 % selectivity, then competes with formaldehyde at intermediate temperatures in the CH 4 conversion over RuO 2 (1 1 0) surface. The present findings suggest that the RuO 2 (1 1 0) surface is a potential catalyst for facilitating ethylene production under mild conditions. [ABSTRACT FROM AUTHOR]

Construction resting on soil and rocks containing montmorillonite (MMT) are prone to damage induced by swelling, which involves a significant release of energy. It is often desirable to enhance these soils to mitigate swelling potential, regulate volume changes, and manage energy release. Experimental findings suggest that increasing temperature is one method to improve these soils, with water content, initial volume, and boundary conditions also influencing the swelling mechanism. This study utilizes ab initio molecular dynamics calculations to explore changes in volume and energy within MMT unit cells at the nanoscale due to temperature variations. The response of unit cells of MMT with varying dimensions and quantities of water molecules to temperature is assessed under constrained and unconstrained conditions. Results indicate that the volume changes and energy release of unit cells in response to temperature are contingent upon the presence of water molecules. In unit cells containing water molecules, both energy and volume decrease with rising temperature, whereas in unit cells devoid of water molecules, energy decreases while volume increases as temperature rises. Given the inherent association of soils with water in natural settings, it can be deduced that increasing temperature presents a viable method for enhancing naturally occurring MMT-dominated soils. Density functional theory calculations demonstrate that alterations in the volume and energy of MMT stem from shifts in interactions among the minerals, cations, and water molecules, as well as intrinsic structural defects like isomorphic substitution and peroxy links within the unit cells. These modifications induce variations in charge carriers and electrical properties, consequently influencing volume and energy changes within MMT unit cells. Additionally, it was observed that the failure of peroxy links can significantly impact the optimal temperature selection for the thermal enhancement of MMT. [ABSTRACT FROM AUTHOR]

In this study, we present a comprehensive first-principles computational investigation focused on the structural characteristics, electronic properties, and coupling integrations of three cationic Gemini surfactants: 12-4-12, 12-3-12, and 12-2-12 ((CH3(CH2)11)(CH3)2-N+-(CH2)n-N+(CH3(CH2)11)(CH3)2, where n = 2, 3, or 4). By employing Density Functional Theory (DFT) computations, we aimed to gain insights into the fundamental aspects of these surfactant molecules, and the intermolecular interactions among these surfactant molecules. We examined different conformers of each surfactant, including parallel, wing, and bent conformers, and compared their relative stability and properties. We elucidated that the complex structural characteristics, electronic properties, and molecular arrangements of the surfactants vary according to the number of carbon atoms in the central spacer. We also conducted experimental Raman spectroscopy on the three surfactants to compare the results with our computational findings. Furthermore, we computed the coupling behaviors of different conformers of 12-4-12 surfactants in order to gain insights into their coupling mechanism. [ABSTRACT FROM AUTHOR]

This study investigates the utilisation of organometallic network frameworks composed of fourth-period transition metals and tetrahydroxyquinone (THQ) in electrocatalytic CO2 reduction. Density functional theory (DFT) calculations were employed in analysing binding energies, as well as the stabilities of metal atoms within the THQ frameworks, for transition metal TM-THQs ranging from Y to Cd. The findings demonstrate how metal atoms could be effectively dispersed and held within the THQ frameworks due to sufficiently high binding energies. Most TM-THQ frameworks exhibited favourable selectivity towards CO2 reduction, except for Tc and Ru, which experienced competition from hydrogen evolution reaction (HER) and required solution environments with pH values greater than 5.716 and 8.819, respectively, to exhibit CO2RR selectivity. Notably, the primary product of Y, Ag, and Cd was HCOOH; Mo produced HCHO; Pd yielded CO; and Zr, Nb, Tc, Ru, and Rh predominantly generated CH4. Among the studied frameworks, Zr-THQ displayed values of 1.212 V and 1.043 V, corresponding to the highest limiting potential and overpotential, respectively, while other metal–organic frameworks displayed relatively low ranges of overpotentials from 0.179 V to 0.949 V. Consequently, it is predicted that the TM-THQ framework constructed using a fourth-period transition metal and tetrahydroxyquinone exhibits robust electrocatalytic reduction of CO2 catalytic activity. [ABSTRACT FROM AUTHOR]

Carbon materials have shown significant potential as catalysts for lithium-oxygen batteries (LOBs). However, the intrinsic carbon sites are typically inert, necessitating extensive modifications and resulting in a limited density of active sites. Here we present C60 as a metal-free cathode catalyst for LOBs, using density functional theory calculations and experimental verifications. The lithiation reactions on the pristine carbon sites of C60 are energetically favorable due to its curved π-conjugation over the pentagon–hexagon networks. The kinetic analysis specifically reveals low energy barriers for Li2O2 decomposition and Li diffusion on C60. Consequently, C60 exhibits significantly higher catalytic activity than typical carbon materials such as graphene and carbon nanotubes. Our electrochemical measurements validate the predictions, notably demonstrating that the intrinsic activity of C60 is comparable to that of noble metals. [ABSTRACT FROM AUTHOR]

The growing demand for lithium, which is essential for the production of batteries, has led to a significant rise in the price of lithium. The quest for novel materials that could enhance battery performance has thus become a key challenge for scientists. In this regard, the author conducted a comparative analysis of materials based on graphene, using density functional theory and ab initio molecular dynamics methods. The materials considered for comparison include graphene, C3B, and C3N. For the calculations, two-layer systems of pristine graphene and graphene modified by substituting carbon atoms with boron and nitrogen were constructed. The stability of these systems was examined using the Quantum Espresso and CP2K software at 0 K and 300 K, respectively. In the search for an alternative to lithium, systems incorporating sodium and lithium intercalated between graphene layers were also included in the comparison. [ABSTRACT FROM AUTHOR]

Infrared (IR) thermal imaging is receiving a great deal of attention due to its wide range of applications. Given multiple issues (like cost and availability) with the inorganic materials currently exploited for IR imaging, there is nowadays a great push of developing organic imaging materials. Carbon‐based materials are known to have significant transparency in the visible and IR regions and some are used as transparent conductors. Here, whether π‐conjugated carbon‐based materials are suitable for long‐wave (LW) and mid‐wave (MW) IR imaging applications is computationally assessed. Using density functional theory calculations, the IR‐vibrational properties of molecules from acenes to coronenes and fullerenes, and of periodic systems like graphene and carbon nanotubes are characterized. Fullerenes, graphenes, and double‐walled carbon nanotubes are found to be very attractive as they are transparent in both the LWIR and MWIR regions, a feature resulting from the absence of hydrogen atoms. Also, it is found that replacing hydrogen atoms in a molecule with deuterium or sulfur atoms can be an efficient way to improve their LWIR or MWIR transparency, respectively. For fused‐ring systems having hydrogen atoms on the periphery, designing molecules with trio CH‐units is another way to enhance the transparency in the LWIR region. [ABSTRACT FROM AUTHOR]

The irradiation of 2-aryl-4-(E-3′-aryl-allylidene)-5(4H)-oxazolones 1 with blue light (456 nm) in the presence of [Ru(bpy)3](BF4)2 (bpy = 2,2′-bipyridine, 5% mol) gives the unstable cyclobutane-bis(oxazolones) 2 by [2+2]-photocycloaddition of two oxazolones 1. Each oxazolone contributes to the formation of 2 with a different C=C bond, one of them reacting through the exocyclic C=C bond, while the other does so through the styryl group. Treatment of unstable cyclobutanes 2 with NaOMe/MeOH produces the oxazolone ring opening reaction, affording stable styryl-cyclobutane bis(amino acids) 3. The reaction starts with formation of the T1 excited state of the photosensitizer 3[Ru*(bpy)3]2+, which reacts with S0 of oxazolones 1 through energy transfer to give the oxazolone T1 state 3(oxa*)-1, which is the reactive species and was characterized by transient absorption spectroscopy. Measurement of the half-life of 3(oxa*)-1 for 1a, 1b and 1d shows large values for 1a and 1b (10–12 μs), while that of 1d is shorter (726 ns). Density functional theory (DFT) modeling displays strong structural differences in the T1 states of the three oxazolones. Moreover, study of the spin density of T1 state 3(oxa*)-1 provides clues to understanding the different reactivity of 4-allylidene-oxazolones described here with respect to the previously reported 4-arylidene-oxazolones. [ABSTRACT FROM AUTHOR]

Herein, a mechanism is proposed as to how thin films formed from a Heusler compound can simultaneously have both perpendicular magnetic anisotropy (PMA) and be half‐metallic. It is proposed that a thin film formed from a half‐metallic full‐Heusler or half‐Heusler compound that is cubic in the bulk can undergo a tetragonal distortion by adopting the lattice constant of the underlayer material during the thin film deposition process. The value of this distortion can be tuned by using underlayer materials with different in‐plane lattice constants. The distortion can thereby be optimized so that it is large enough to give rise to sufficient PMA, while, simultaneously, small enough to retain the half‐metallic properties (and, therefore, high tunneling magnetoresistance properties) of the Heusler compound. Density functional theory (DFT) calculations that are carried out for 90 full‐Heuslers and 147 half‐Heuslers that have been identified in the literature as half‐metals show that of these, 14 full‐Heusler and 59 half‐Heusler compounds display both half‐metallicity and PMA for optimal tetragonal distortions. [ABSTRACT FROM AUTHOR]

The aromatic C(sp2)-H functionalization of unprotected naphthols with α-phenyl-α-diazoesters under mild conditions catalyzed by CuCl and CuCl2 exhibits high efficiency and unique ortho-selectivity. In this study, the combination of density functional theory (DFT) calculations and experiments is employed to investigate the mechanism of C-H functionalization, which reveals the fundamental origin of the site-selectivity. It explains that CuCl-catalyzed ortho-selective C-H functionlization is due to the bimetallic carbene, which differs from the reaction catalyzed by CuCl2 via monometallic carbene. The results demonstrate the function of favourable H-bond interactions on the site- and chemo-selectivity of reaction through stabilizing the rate-determining transition states in proton (1,3)-migration. [ABSTRACT FROM AUTHOR]

Nitrogen-doped iron/zinc bimetallic single atom catalysts (FeZn SCA-N@C), characterized by FeZnN4 active configuration, are synthesized to exhibit oxidase-like activity, facilitating the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to yield the blue product, oxTMB, in the presence of oxygen (O 2). [Display omitted] • Three single atom catalysts (FeZn SAC-N@C, Fe SAC-N@C, and Zn SAC-N@C) were synthesized and characterized. • The oxidase-mimicking activity followed the order: FeZn SAC-N@C > Fe SAC-N@C > Zn SAC-N@C. • The anchoring of metal zinc in atomically dispersed Fe-N-C can enhance its oxidase-like activity. • The catalytic mechanism of the synthesized oxidase-like SACs was elucidated by EPR and DFT calculations. • FeZn SAC-N@C demonstrates potential as a colorimetric sensor for detecting ascorbic acid and nitrite. The burgeoning interest in single atom catalysts (SACs) stems from their exceptional oxidase-mimicking capabilities, driving substantial advancements in this field. Nevertheless, a critical knowledge gap remains regarding the influence of Zn incorporation on the oxidase-like activity of atomically dispersed Fe-N-C catalysts. This study successfully synthesized and comprehensively characterized three distinct SACs (FeZn SAC-N@C, Fe SAC-N@C, and Zn SAC-N@C) using TEM, HAADF-STEM, XRD, XPS, BET, ICP-MS, and XAFS techniques. Activity assays revealed that FeZn SAC-N@C exhibited the highest oxidase-mimicking activity, with Fe SAC-N@C displaying moderate activity, whereas Zn SAC-N@C did not exhibit oxidase-like behavior. The superior oxidase-like activity of FeZn SAC-N@C is attributed to its enhanced O 2 activation capacity, characterized by a high free energy of 0.90 eV in the rate-determining reaction step, surpassing those of Fe SAC-N@C (0.85 eV) and Zn SAC-N@C (0.71 eV). EPR and DFT calculations elucidated the catalytic mechanism of FeZn SAC-N@C, involving the generation of O 2 − radicals. As a proof-of-concept, FeZn SAC-N@C demonstrates potential as a colorimetric sensor for detecting ascorbic acid and nitrite, achieving a limit of detection of 0.77 μM for ascorbic acid and 0.16 μM for nitrite. These findings open a new avenue for configuring bimetallic atomically dispersed catalysts with oxidase-like activity in future research. [ABSTRACT FROM AUTHOR]

• Two-step synthesis method prepares the quaternary alloy catalyst for enhancing efficiency and reproducibility. • A significant reduction in platinum content to approximately 10% in catalysts without compromising catalytic performance. • PtCoSnCu/N-C catalyst with mass activity and specific activity up to 9.73 and 9.75 times higher than commercial Pt/C. • DFT calculations reveal the optimization of electronic structure and the synergistic effect of atoms on the catalyst surface. The quest for platinum-based catalysts with enhanced catalytic efficacy and durability during the methanol oxidation reaction (MOR) has been a focal point in energy conversion science. Traditional platinum-based catalysts are often constrained by their high platinum content, which escalates economic costs and complicates experimental protocols. In this study, we introduce a low-platinum-loaded catalyst synthesized via a two-step method, which incorporates a four-component alloy. This innovative approach significantly reduces platinum content while maintaining superior catalytic performance through precise control over the alloy's composition and structure. The two-step synthesis methodology streamlines the conventional multi-step processes, enhancing the catalyst preparation's efficiency and reproducibility. The resulting PtCoSnCu/N-C alloy catalyst exhibits remarkable catalytic activity in methanol solution, with mass activity and specific activity that are 9.73 and 9.75 times higher, respectively, than those of commercial platinum on carbon (Pt/C) catalysts. Notably, the optimized PtCoSnCu/N-C alloy catalyst demonstrates exceptional long-term stability, outperforming Pt/C in aging and extended stability tests. Density functional theory (DFT) calculations elucidate the optimization of the electronic structure and the synergistic effect of surface atoms in the PtCoSnCu/N-C catalyst, which mitigates the adsorption energy of CO molecules and enhances the utilization rate of active sites during the oxidation process. This research presents a paradigm-shifting low-platinum catalyst strategy for methanol fuel cells, establishing a theoretical foundation for catalyst design and optimization. [ABSTRACT FROM AUTHOR]

Highly efficient electrochemical water splitting is of prime importance in hydrogen energy but is suffered from the slow kinetics at the anodic oxygen evolution reaction. Herein, combining the surface activation with the heterostructure construction strategy, the CoP/Fe‐Co9S8 heterostructures as the pre‐catalyst for highly efficient oxygen evolution are successfully synthesized. The catalyst only needs 156 mV to reach 10 mA cm−2 and keeps stable for more than 150 h. Inductively coupled plasma optical emission spectrometry, in situ Raman spectroscopy and density functional theory calculations verify that the introduction of Fe can promote the formation of highly active Co(IV)–O sites and lead to a self‐termination of surface reconstruction, which eventually creates a highly active and stable oxygen evolution catalytic surface. Besides, the catalyst also demonstrates high hydrogen evolution reaction activity with an overpotential of 62 mV@10 mA cm−2. Benefiting from its bifunctionality and self‐supporting property, the membrane electrode assembly electrolyzer equipped with these catalysts achieves high overall water splitting efficiency of 1.68 V@1 A cm−2. [ABSTRACT FROM AUTHOR]

The paper presents research on chloride minerals of natural origin from Kłodawa (Poland), i.e., colorless, blue and purple halite as well as colorless sylvite. Selected samples of minerals were studied by chemical analysis (ICP-OES, ICP-MS, titration methods) and crystallographic measurements. Then, for the tested halides, research was carried out using far-infrared spectroscopy. Spectroscopic studies confirmed the simple way of distinguishing NaCl and KCl minerals using far-infrared spectroscopy, known in the literature. The novelty is that the article presents for the first time the experimental far infrared spectra of natural blue and purple halite. It was observed that the blue (178 cm−1) and purple (176 cm−1) halites have the strongest infrared band slightly shifted towards higher wavenumbers compared to colorless halite (174 cm−1). As part of the work, the infrared spectra of the crystal structure models of sodium and potassium chloride were calculated for the first time using the density functional theory (with the B3LYP functional and the 6-31G* basis set, 125-atom model). The proposed approach can be used not only as a powerful method differentiating NaCl and KCl minerals, but it can also help with understanding of different defects in crystal lattices for naturally occurring halides and crystals of other minerals. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO2 to valuable fuels and chemicals can not only alleviate the energy crisis but also improve the atmospheric environment. The key is to develop electrocatalysts that are extremely stable, efficient, selective, and reasonably priced. In this study, spin-polarized density function theory (DFT) calculations were used to comprehensively examine the catalytic efficacy of transition metal-hexaaminobenzene (TM-HAB) monolayers as single-atom catalysts for the electroreduction of CO2. In the modified two-dimensional TM-HAB monolayer, our findings demonstrate that the binding of individual metal atoms to HAB can be strong enough for the atoms to be evenly disseminated and immobilized. In light of the conflicting hydrogen evolution processes, TM-HAB effectively inhibits hydrogen evolution. CH4 dominates the reduction byproducts of Sc, Ti, V, Cr, and Cu. HCOOH makes up the majority of Zn's reduction products. Co's primary reduction products are CH3OH and CH4, whereas Mn and Fe's primary reduction products are HCHO, CH3OH, and CH4. Among these, the Ti-HAB reduction products have a 1.14 eV limiting potential and a 1.31 V overpotential. The other monolayers have relatively low overpotentials between 0.01 V and 0.7 V; therefore, we predict that TM-HAB monolayers will exhibit strong catalytic activity in the electrocatalytic reduction of CO2, making them promising electrocatalysts for CO2 reduction. [ABSTRACT FROM AUTHOR]

Overlithiated layered oxides (OLOs) that achieve high specific capacity (>250 mAh/g) owing to additional anionic redox are promising cathode materials for lithium rechargeable batteries. However, the anionic redox at high voltages leads to structural degradation of OLO with transition metal (TM) migration and oxygen loss. Such structural instability leads to voltage and capacity fading, which impedes the commercial use of OLO. In this study, first-principles-based high-throughput computational screening is performed to identify promising dopants to improve the structural stability of OLO. Li 1.15 Ni 0.19 Co 0.11 Mn 0.56 O 2 is constructed as a pristine structure to evaluate the performances of the 36 dopants. Several criteria, including thermodynamic stability, TM–O bond length, interlayer spacing, volumetric shrinkage, oxygen stability, dopant inertness, and specific energy, are considered in the discharged and charged states. Among the considered dopant candidates, two (Si and Ga) fulfill all the criteria; hence, they are believed to improve the structural stability of the OLO cathode. The current analysis provides comprehensive guidelines for the synthesis of doped OLO while satisfying long-term cyclability and high-energy requirements. [Display omitted] • OLOs achieve >250 mAh/g due to anionic redox but suffer structural degradation. • High-throughput screening identifies dopants to improve OLO stability. • Li 1.15 Ni 0.19 Co 0.11 Mn 0.56 O 2 is used to evaluate 36 dopant candidates. • Si and Ga dopants meet all criteria for improving OLO structural stability. • This study offers guidelines for OLO synthesis with long-term cyclability. [ABSTRACT FROM AUTHOR]

An integrated theoretical-experimental investigation is performed to understand the photocatalytic and optical properties of Ag/SrTiO 3 nanocomposite (Ag/STO). Theoretical investigation reveals that the catalytic activity of Ag/STO is increased when Ag particle size is smaller, while the opposite correlation is observed for its visible-light absorbance efficiency. These insights suggest that efficient Ag/STO photocatalyst needs to be balanced between the active interfacial site density and visible-light absorbance intensity by carefully controlling the Ag dosage. Furthermore, reactive oxygen species that are responsible for the oxidative degradation of organic pollutant on Ag/STO could be identified from Density Functional Theory (DFT) calculations. Comprehensive experiments are carried out using Rhodamine-B (RhB) photodegradation to test the activity of Ag/STO in wastewater treatment application and excellently validate those theoretical predictions. Over series of synthesized Ag/STO composites with different Ag contents, the optimum 1 % wt. Ag loading has the highest 92.8 % efficiency in RhB photodegradation after 1 hour of light irradiation. Trapping experiments also confirm the crucial role of O 2 and OH species, which was predicted from DFT calculations, as the primary oxidizing agents for the degradation of RhB. This work provides a useful framework to develop novel plasmonic nanocomposites for other photocatalytic applications. [Display omitted] • An integrated theoretical-experimental investigation into the catalytic and optical properties of Ag/SrTiO 3 nanocomposite. • Chemical interaction between Ag and SrTiO 3 is confined narrowly within two atomic Ag layers above the support. • The interfacial Ag/SrTiO 3 sites are active in generating reactive oxygen species which are necessary for oxidation reactions. • Ag dosage must be optimized to balance active site density and photon absorbance intensity for photocatalytic applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synchronous preparation of cobalt nanoparticles decorated graphene electrodes through laser scribing. • A novel approach to fabricate metal particles decorated LIG electrodes for flexible MSCs. • The optimized MSCs exhibit dramatically improved electrochemical performance. • The devices exhibit outstanding potential for practical applications. • DFT calculations theoretically illustrate the influence of cobalt decoration. Transition metal nanoparticles-graphene nanocomposites incorporate the advantages of graphene and metal nanoparticles, which arouse extensive attention. Here, we design a novel, facile and versatile method for in-situ synthesis of laser-induced porous graphene (LIG) decorated with cobalt particles (Co). The LIG/Co nanocomposites are fabricated through one-step laser direct scribing on a customized film composed of polyimide (PI) powder, polyvinyl alcohol (PVA), and cobalt chloride (CoCl 2 ·6H 2 O) precursors. Benefiting from the unique properties of Co nanoparticles embedded LIG, the obtained optimal in-plane micro-supercapacitors (IMSC) based on LIG/Co-1.5 possesses an excellent areal capacitance of 110.11 mF cm−2 and a superior energy density of 9.79 μWh cm−2, which are about 79 times that of pure LIG-based IMSCs. Simultaneously, the LIG/Co-1.5 MSCs also present good cycling stability, remarkable modular integration capability, and outstanding mechanical flexibility, showing potential for practical applications. Additionally, the density functional theory (DFT) calculations indicate that the decorating of cobalt particles elevates electron transfer. Moreover, the interaction between electrolyte and electrodes is also improved with the introduction of cobalt particles. Therefore, this strategy offers a new avenue for facile and large-scale manufacturing of various metallic atoms in-situ decorating in porous graphene. [ABSTRACT FROM AUTHOR]

A novel bis-isoxazole was synthesized from (R)-Carvone and p-methylbenzaldoxime, via two successive [3+2] cycloaddition reactions (32CA). The newly obtained bis-isoxazole has been fully characterized by HRMS and NMR spectroscopy. The HMBC experiment was performed to determine the stereo and the regioselectivity of the reaction. The electrochemical behavior of the studied compound, in oxidation and reduction processes, was examined using the cyclic voltammetry technique. In addition, the regioselectivity of the [3+2] cycloaddition reaction and the molecular structure of the title compound was performed by density functional theory (DFT). The HOMO and LUMO orbitals were investigated to determine the electronic properties of the synthesized compound. Besides, the global reactivity indexes were used to explain the regioselectivity for the formation of the bis-isoxazole, the theoretical results are in good agreement with experimental findings. [ABSTRACT FROM AUTHOR]

• A selective leaching technique has been invented. • The feasibility of this technique was first demonstrated. • A spent LiNi 1/3 Co 1/3 Mn 1/3 O 2 material was recycled without a separation step. Efficient recycling of high-value metals from spent cathode materials is important in that it not only alleviates the severe shortage of raw material supply but also addresses the environmental and safety issues associated with the disposal of these materials. Here, we report a selective leaching strategy by virtue of the defect-induced lattice instability. In contrast to the traditional "primary leaching – multistep separation" process, this technique enables simultaneous recovery and separation of value metals from the waste cathode by selective dissolution. The feasibility of this technique was first demonstrated by density functional theory (DFT) calculations, and then confirmed by laboratory studies in which a spent LiNi 1/3 Co 1/3 Mn 1/3 O 2 material was successfully recycled, where the recoveries of Li, Ni/Co and Mn reached close to 100%, 99.5%/98.2% and 100%, respectively, without the need for a separation step. The recovery of Li, Ni/Co and Mn uses oxalic acid, phosphoric acid and sulfuric acid as leaching agents, respectively. We believe that this work has both practical and theoretical significance, in that the strategy has the potential to be expanded to the recovery/recycling of many other spent materials, and that the atomic-scale insight on the relation between vacancies and lattice stability offers new perspective for developing advanced recycling strategies. [ABSTRACT FROM AUTHOR]

First‐principles calculations of the crystal structure and elastic properties of a range of oxyorthosilicates R2SiO5 (R denotes rare‐earth ion) are performed in the framework of density functional theory (DFT) with hybrid functionals. The elastic moduli, sound velocities, Debye temperature, and minimum thermal conductivity coefficient are calculated for Lu2SiO5 in good agreement with the experiment, and a prediction of these parameters for a range of R2SiO5 is made. It is shown that La2SiO5 and Pr2SiO5 have the minimum thermal conductivity from a range of oxyorthosilicates. [ABSTRACT FROM AUTHOR]

First‐principles calculations of the crystal structure and elastic properties of a range of oxyorthosilicates R2SiO5 (R denotes rare‐earth ion) are performed in the framework of density functional theory (DFT) with hybrid functionals. The elastic moduli, sound velocities, Debye temperature, and minimum thermal conductivity coefficient are calculated for Lu2SiO5 in good agreement with the experiment, and a prediction of these parameters for a range of R2SiO5 is made. It is shown that La2SiO5 and Pr2SiO5 have the minimum thermal conductivity from a range of oxyorthosilicates. [ABSTRACT FROM AUTHOR]

Facile wet chemical synthesis was utilized to synthesize nanoflowers of copper selenide (CuSe) that exhibited exceptional room temperature ammonia (NH 3) gas sensing capability. Observations of surface morphology revealed the presence of petal-like structures arranged in a flower-like pattern. The layered materials have been analyzed for their crystalline structure, phase, composition, and band gap by utilizing X-ray diffraction, Transmission Electron Microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy, UV-Vis, respectively. At ambient conditions, CuSe nanoflowers-based sensor demonstrated exceptional sensitivity, reaching up to 79% (200 ppm NH 3) with short response and recovery time of 12.9 s and 6.3 s, respectively, at 5 ppm gas concentration. The sensor exhibited rapid response and recovery times, a broad concentration range, long-term stability over extended periods, exceptional specificity towards NH 3 , and good repeatability owing to its distinct flower-shaped structures assembled in thin layers. Density Functional Theory simulations were conducted to investigate the interactions between NH 3 and CuSe. Our findings revealed an increase in the adsorption energy of NH 3 on CuSe, indicating a stronger binding affinity. We observed a higher charge transfer from CuSe to NH 3 , which suggests an increase in conductivity. This increase in conductivity enhances the superior sensing capability observed in the experimental results. [Display omitted] • CuSe nanoflowers assemble in petal-like structure, prepared by wet chemical synthesis • It has potential application in NH 3 gas sensing at room temperature • High response (12.7%), short response/recovery time (12.9 s/6.3 s) at 5 ppm NH 3 gas. • It has long-term stability and good repeatability • DFT simulation is performed to understand the mechanism. [ABSTRACT FROM AUTHOR]

We found the nickel-based phosphides are actually acting as pre-electrocatalysts in OER, and also in battery reactions of rechargeable Zn-air batteries, which are well disclosed by detailed experimental and theoretical investigations. [Display omitted] Zinc-air batteries (ZnABs) with high theoretical capacity and environmental benignity are the most promising candidates for next-generation electronics. However, their large-scale applications are greatly hindered due to the lack of high-efficient and cost-effective electrocatalysts. Transition metal phosphides (TMPs) have been reported as promising electrocatalysts. Notably, (Ni 1 −x Cr x) 2 P (0 ≤ x ≤ 0.15) is an unstable electrocatalyst, which undergoes in-situ electrochemical oxidation during the initial oxygen evolution reaction (OER) and even in the activation cycles, and is eventually converted to Cr-NiOOH serving as the actual OER active sites with high efficiency. Density functional theory (DFT) simulations and experimental results elucidate that the OER performance could be significantly promoted by the synergistic effect of surface engineering and electronic modulations by Cr doping and in-situ phase transformation. The constructed rechargeable ZnABs could stably cycle for more than 208 h at 5 mA cm−2, while the voltage degradation is negligible. Furthermore, the developed catalytic materials could be assembled into flexible and all-solid-state ZnABs to power wearable electronics with high performance. [ABSTRACT FROM AUTHOR]

High‐resolution (0.12 a.u.) electron momentum density projections (Compton profiles) of a hexagonal Zn single crystal have been measured along five high‐symmetry directions in reciprocal space. The experiment was performed with the use of 115.6 keV synchrotron radiation on the BL08W station at SPring‐8. The quality of the measured Compton profiles is significantly better than that of previous medium‐ and high‐resolution data. The experimental data were compared with the corresponding theoretical Korringa–Kohn–Rostoker (KKR) and density functional theory (DFT) calculations. Some minor and major differences between the two theoretical band‐structure calculations have been observed. However, the good quality experimental results indicate their better agreement with DFT. [ABSTRACT FROM AUTHOR]

Although the methods of chemical reduction of graphene oxide have been intensively and well investigated, the reduction mechanism is still ambiguous to date. The reduction mechanisms proposed so far were limited to explain a specific reducing agent rather than a general accessible approach. Here, we suggest that the core issue of chemical reduction of graphene oxide is the reduction of hydroxyl groups. Fundamental reactions mechanisms - E1 and E1cB - are proposed and studied as a general applicable but conclusive reduction mechanisms. Density Functional Theory calculation was used to investigate both reaction pathways for the acid- and base-induced reductions. The calculation results show that both reaction pathways are favorable on kinetics and thermodynamics. By applying this reduction mechanism, we developed NaSH as a novel and efficient reducing agent to reduce GO at room temperature, which further confirms the feasibility of the proposed reaction pathways. This work is thus able to investigate possible reaction pathways for various chemical reduction methods and will help to mature novel reduction approaches. Image 1 • We suggest that the core issue of chemical reduction of graphene oxide is the reduction of hydroxyl groups. • E1 and E1cB - are proposed as the general applicable reaction mechanism for chemical reduction of graphene oxide. • Density Functional Theory calculation results proof both E1 and E1cB reduction pathways are favorable. • Developed NaSH as a novel and efficient reducing agent to reduce GO at room temperature. [ABSTRACT FROM AUTHOR]

• Eutectic mixtures of the APIs with the amino acids were designed. • Physiochemical properties in default and water were studied. • Solubility of designed eutectic mixtures of APIs have been determined and discussed. • Solubility of the designed eutectic mixtures is better than the APIs were found. Solubility is a major concern for many active pharmaceutical ingredients (APIs) and drugs. Owing to their better solubility, biodegradability and low toxicity of APIs and drugs, eutectic mixtures are emerging as the system to enhance their solubility with no loss of biological activity. In the present work, authors have taken camizestrant, deucravacitinib, and iclepertin as the active pharmaceutical ingredients (API) because they have poor solubility in water. Authors have designed eutectic mixtures (EMs) of the selected APIs with the amino acids (aspartic acid, lysine, phenylalanine, and proline) and studied for their physiochemical properties in default and water using density functional theory calculations, performed by Gaussian. The solubility of the APIs, amino acids and the designed eutectic mixtures of APIs have been determined and discussed using the dipole moment. The results showed that the solubility of the designed eutectic mixtures have better aqueous solubility than the APIs alone. Further, molecular dynamics (MD) simulations were done for APIs and EMs to study their stability and interactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • SiP/TiO 2 S-scheme heterojunction photocatalysts were first applied for degradation of organic pollutants. • Compared with powder catalysts, SiP/TiO 2 photocatalysts are easily recyclable and environmental-friendly. • DFT calculations and experimental results reveal internal electric fields in SiP/TiO 2 heterojunction accelerate the transport and separation of photogenerated carriers. • Toxicity assessment and antimicrobial test results demonstrate low toxicity of photocatalytic processes. Photocatalysis is considered to be an effective approach for eliminating intractable organic pollutants in wastewater. However, its inefficiency is attributed to the slow transport and quick complexation of photogenerated carriers. Herein, we proposed a novel SiP/TiO 2 S-scheme heterojunction photocatalyst synthesized by hydrothermal method. And this photocatalyst was firstly used for the efficient degradation of norfloxacin, degrading 90.89% of norfloxacin (NOR) in 100 min which was 3 times higher than the degradation efficiency of TiO 2 (29.98%). Results from spectral analysis and density functional theory (DFT) calculations confirm that an internal electric field (IEF) exists in the SiP/TiO 2 heterojunction. This IEF is advantageous for transporting and separating photogenerated carriers. Unlike conventional powder photocatalysts, this photocatalyst grown on conductive glass is not only simple to recycle, but also prevents environmental contamination. This research opens up new options for designing and applying heterojunction catalysts. [ABSTRACT FROM AUTHOR]

Highlights: • Clarify the effect of vacancy on H 2 S dissociation and H atom diffusion on Fe(1 0 0) surfaces. • Demonstrate the effects of adjacent vacant atom on H atom diffusion. • Reveal the minimum energy-diffusion path of the H atom from the Fe(1 0 0) surfaces into the bulk Fe. Abstract Vacancy defects on an iron surface have a great influence on the occurrence of hydrogen embrittlement. The adsorption/dissociation mechanism of H 2 S and the diffusion behavior of H atoms were calculated by first-principles spin-polarization density functional theory (DFT) on defect-free and vacancy-defective Fe(1 0 0) surfaces. The results show that the maximum dissociation energy barriers of H 2 S on the Fe(1 0 0) surface of defect-free and first-layer vacancy-defective Fe are 0.35 and 0.17 eV, respectively, indicating that the reactivity of the vacancy-defective Fe(1 0 0) surface is moderately increased. The existence of vacancy defects changes the preferential H atom diffusion entrance to the subsurface and shortens the diffusion path. For H diffusion in bulk Fe(1 0 0), it is found that H atoms diffuse via a tortuous path from one tetrahedral-site to a neighboring tetrahedral-site rather than diffusing through a linear trajectory. Moreover, the previously suggested path via the octahedral site is excluded due to its higher barrier and the rank of the saddle point. Diffusion barriers computed for H atom penetration from the surface into the inner-layers are approximately 0.54 eV (except for second-layer vacancy defects), which are all greater than the activation energy for dissociation of H 2 S on the Fe(1 0 0) surfaces. This suggests that H diffusion is more probable than H 2 S dissociation as the rate-limiting step for hydrogen permeation into the bulk Fe(1 0 0). [ABSTRACT FROM AUTHOR]

Abstract—: This paper presents a theoretical study of the effects of crystal structure and Mn and Co substitutions for Cd on the electronic structure of the topological material Cd3As2. We have carried out density functional theory calculations of the band structure and density of states in tetragonal and cubic Cd3As2, as well as in Cd3 -xMnxAs2 and Cd3 -xCoxAs2 crystals. The results indicate that the band structure of the cubic Cd3As2 phase differs significantly from that of a Dirac semimetal, characteristic of the tetragonal phase. It has also been shown that, after Co substitution for 1/24 of the Cd atoms, the structure of the density of 3d electron states is similar to that of the density of states in the magnetic semiconductor Cd3 -xMnxAs2, with a characteristic minimum at the Fermi energy. At the same time, in the case of analogous Mn substitution for Cd, the density of d-electron states has no such minimum. [ABSTRACT FROM AUTHOR]

Abstract—: This paper presents a theoretical study of the effects of crystal structure and Mn and Co substitutions for Cd on the electronic structure of the topological material Cd3As2. We have carried out density functional theory calculations of the band structure and density of states in tetragonal and cubic Cd3As2, as well as in Cd3 -xMnxAs2 and Cd3 -xCoxAs2 crystals. The results indicate that the band structure of the cubic Cd3As2 phase differs significantly from that of a Dirac semimetal, characteristic of the tetragonal phase. It has also been shown that, after Co substitution for 1/24 of the Cd atoms, the structure of the density of 3d electron states is similar to that of the density of states in the magnetic semiconductor Cd3 -xMnxAs2, with a characteristic minimum at the Fermi energy. At the same time, in the case of analogous Mn substitution for Cd, the density of d-electron states has no such minimum. [ABSTRACT FROM AUTHOR]

A robust and fast method is presented that provides a simple real‐space convergent solution for identifying equilibrium orientations of crystallization H2O molecules in ionic crystals, on the basis of zero net torque. The predicted H2O orientations constrained by rotational equilibrium are compared with neutron scattering experiments and/or ab initio density functional theory (DFT) calculations. The comparison shows that predicted and observed H2O orientations are consistent, demonstrating the reliability of the reported torque method. Moreover, the rotational equilibrium conditions predict an alternative, not previously observed, H2O orientation in kernite [Na2B4O6(OH)2·3H2O], and this may explain anomalously large displacement parameters that have been reported for this mineral. Complementary DFT computations corroborate that the two orientations are geometrically distinct and energetically near degenerate. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-doped La 2 CuO 4 had been synthesized using melamine as the N precursor. • N-doped La 2 CuO 4 showed enhanced catalytic activity and stability. • Density Functional Theory (DFT) calculations were performed to verify the results. • A mechanism of phenol degradation was proposed. • The toxicity of degradation intermediates was greatly reduced. Herein, N-doped perovskite La 2 CuO 4 (LCO) (N-LCO(M)) was fabricated by sol–gel rapid calcination method using melamine (M) as N source/ligand, and applied for the catalytic wet air oxidation (CWAO) to degrade high-concentration phenol-containing simulated wastewater. The experimental results exhibited that N-LCO(M) illustrated enhanced phenol degradation efficiency. Thereinto, 87.9% COD degradation efficiency was achieved in simulated wastewater containing 8000 mg/L phenol, while for undoped LCO prepared with citric acid (CA) as ligand (LCO(CA)) was only 43.8%. The systematic characterizations and density functional theory (DFT) calculations were utilized to verify the above results. The results revealed that N doping favored the formation of more oxygen vacancies (*) and facilitated the charge transfer between Cu and O. More oxygen vacancies (*) reinforced the ability of N-LCO(M) to adsorb O 2 to form reactive oxygen species (O*), and meanwhile, the charge transfer between Cu and O was manifested as the redox cycle of the catalytic active metal Cu2+/Cu1+. The redox cycle also promoted the formation of O 2 − and HO, making the more exhaustive degradation of phenol. This successfully proved that N doping was core to improving the activity and stability of N-LCO(M). Moreover, a possible mechanism of phenol degradation was proposed based on the experimental results and DFT calculations. Eventually, the toxicity of the intermediate products was further evaluated by quantitative structure–activity relationship (QSAR) analysis, showing the significantly reduced toxicity of the intermediate products. Overall, the proposed CWAO technique is a green and promising wastewater treatment method. [ABSTRACT FROM AUTHOR]

Dnsity functional theory (DFT) calculations have been carried out for the highly selective cis-1,4-polymerization of butadiene catalyzed by a cationic rare-earth metal complex bearing an ancillary PNP ligand. It has been found that the chain initiation and propagation of butadiene polymerization occurs via the favorable cis-1,4-insertion route. The trans-1,4 and 1,2-insertion are unfavorable both kinetically and thermodynamically. The chain growth follows the π-allyl-insertion mechanism. The analyses of energy decomposition of transition states indicate that the likelihood of rival insertion pathways is predominantly controlled by the interaction energy of butadiene with a metal center and the deformation energy of butadiene moiety. The electronic factor of the central metal has a decisive influence on the cis- vs. trans-insertion and the regioselectivity (cis-1,4- vs. cis-1,2-insertion) is mainly determined by steric hindrance. Tetrahydrofuran (THF) coordination made monomer insertion less favorable compared with THF-free case and had more noticeable impact on the trans-monomer insertion compared with the cis case. During the chain propagation, cis-insertion of monomer facilitates THF de-coordination and the THF molecule could therefore dissociate from the central metal. [ABSTRACT FROM AUTHOR]

In this study, GeO x films were produced by radio frequency magnetron sputtering (RFMS) under varying oxygen percentages. The structural and optical properties of films grown have been studied experimentally and theoretical calculations have been presented using density functional theory (DFT). Considering the x-ray diffraction (XRD) analysis, Ge (111) peak was observed in the as-deposited film produced only at 2% oxygen percentage. In order to emerge crystal phases, all the amorphous films were annealed at 900 °C under atmospheric conditions. It was found that the intensity of the (101) peak increased as the oxygen percentage increased. At the same time, film grown at 2% oxygen percentage was annealed at different annealing temperatures sequentially at 850, 900, and 950 °C. As a result, the polycrystalline properties changed as the annealing temperature increased. It was found that the optical properties of the films grown are strongly dependent on the oxygen percentage. As the oxygen percentage has changed, the energy band gap has increased to the values 2.30, 2.31, 2.58, and 6.28 eV. There are Ge-O-Ge antisymmetric stretching peaks appeared at 861.51 cm−1, 949.94 cm−1 and symmetric stretching of hexagonal peaks at 516.34 cm−1, 546.29 cm−1, 581.95 cm−1. The energy band gap results of the density functional theory (DFT) calculations are in good agreement with the experimental observations. [ABSTRACT FROM AUTHOR]

[Display omitted] • A facile strategy is developed to synthesize multiphase Fe-based catalyst. • The Fe/Fe 3 C/FeN 0.0324 @N-GC exhibits excellent pH-universal ORR activity. • It possesses better battery performance than Pt/C in alkaline and neutral media. • The activity is attributed to the synergy among Fe-based sites dominated by Fe 3 C. • The active of Fe-based sites is probed by DFT calculation: Fe 3 C > Fe > FeN 0.0324. Iron-based nitrogen-doped carbonaceous materials are currently the most promising alternative towards oxygen reduction reaction (ORR) electrocatalysts due to the highly efficient active sites of single-atom Fe-N X coordination. However, the fact that iron-containing nanocrystals are easier to form during pyrolysis without additional tuning while providing activity comparable to single-atom sites cannot be ignored. Herein, we propose a facile and efficient strategy to synthesize iron nanocrystals sites with multiphase embedded in porous nitrogen-doped graphitized carbon (Fe/Fe 3 C/FeN 0.0324 @N-GC-X, X = 700, 850, and 1000). Based on highly active Fe 3 C@N-GC sites and the synergistic effect of Fe 3 C-dominated multiple iron-based, Fe/Fe 3 C/FeN 0.0324 @N-GC-850 exhibits excellent electrocatalytic activity towards ORR in pH-universal media. Specifically, it exhibits satisfactory onset potential (E onset), half-wave potential (E 1/2) and stability, and thus surpassing the benchmark Pt/C in both alkaline and neutral media as well as approaching Pt/C in acidic media. When employed as an air cathode in zinc-air batteries (ZABs), it also presents higher open-circuit voltage (OCV), discharge voltage plateaus, capacity, and peak power density compared with Pt/C. Density functional theory (DFT) calculations demonstrate that Fe 3 C (2 2 0)/N-GC has lower activation energy during ORR process and the overpotential generated by Fe 3 C/N-GC (0.7 V) is obviously less than one of Fe/N-GC (1.37 V) and FeN 0.0324 /N-GC (1.69 V). [ABSTRACT FROM AUTHOR]

Biochanin A ( BnA ) a natural o -methylated isoflavone, is isolated from the leaves of Eupatorium adenaphorum and is effectively utilized as a sensor probe for copper ion with good selectivity and sensitivity. The effect with the presence of other metal ions is also investigated and BnA is found to be selective towards Cu 2+ ion over other metal ions such as Zn 2+ , Sn 2+ , Ni 2+ , Ag + , Bi 2+ , Pb 2+ , Co 3+ , In 3+ , Mn 2+ , Fe 2+ , Li + , Hg 2+ and Ca 2+ at pH 7.1 with a detection limit upto 1.0 × 10 −6 mol L −1 . The sensor probe BnA exhibits selective fluorescence quenching via an intramolecular charge transfer (ICT) upon addition of Cu 2+ . The proposed mechanism is strongly supported by TD-DFT calculations and the 1:1 complex ( BnA–Cu 2+ ) formation is confirmed by ESI-MS and Job's plot. [ABSTRACT FROM AUTHOR]

In the title compound, [Cu(C7H3N2O4)(C4H5N2)(H2O)], (I), pyridine-2,6-dicarboxylate (pydc2−), 2-aminopyrimidine and aqua ligands coordinate the CuII centre through two N atoms, two carboxylate O atoms and one water O atom, respectively, to give a nominally distorted square-pyramidal coordination geometry, a common arrangement for copper complexes containing the pydc2− ligand. Because of the presence of Cu... Xbridged contacts ( X = N or O) between adjacent molecules in the crystal structures of (I) and three analogous previously reported compounds, and the corresponding uncertainty about the effective coordination number of the CuII centre, density functional theory (DFT) calculations were used to elucidate the degree of covalency in these contacts. The calculated Wiberg and Mayer bond-order indices reveal that the Cu...O contact can be considered as a coordination bond, whereas the amine group forming a Cu...N contact is not an effective participant in the coordination environment. [ABSTRACT FROM AUTHOR]

The reaction of [3,5-Ph2-C2N3S]2 with [CpCr(CO)3]2 in toluene at room temperature forms an adduct via a Cr-S bond, formulated as CpCr(CO)3SN3C2Ph2, which has fitting NMR, IR, and combustion analysis data. The structure was determined by a single-crystal X-ray structure diffraction study ( P21/ n, a = 8.4611(17) Å, b = 20.509(4) Å, c = 11.757(2) Å, β = 104.453(7)°). The Cr-S bond length of 2.4908(11) Å corresponds to a bond order of 1.0 from >90 values for CpCr(CO) x or Cp*Cr(CO) x moieties ( x = 2, 3) bonded to S, which are used to establish a Pauling-type bond order scale specific to this class of compounds. Similar reactions of fluorinated thiatriazinyls derived from [3-Ph-5-CF3-C2N3S]2 or [4-MeOC6H4-5-CF3-C2N3S]2 are accompanied by the loss of CO to produce CpCr(CO)2SN3C2PhCF3 ( P1, a = 8.0929(8) Å, b = 10.3160(10) Å, c = 11.2405(11) Å, α = 70.032(2)°, β = 72.076(2)°, γ = 82.375(2)°) and CpCr(CO)2SN3(CCF3)(C6H4OCH3) ( P21/ c, a = 8.1311(7) Å, b = 24.284(2) Å, c = 9.1025(8) Å, β = 97.218(2)°), also fully characterized by spectroscopy and crystallography. Their measured Cr-S bond lengths, 2.2987(14) and 2.2965(11) Å, correspond to bond orders of 1.5. (U/R)B3PW91/6-311+G(2df,2p)//B3PW91/6-31G(2d,p) hybrid density functional theory (DFT) calculations show that the tricarbonyl complex has an unusual σ bond. However, the dicarbonyl complexes of the fluorinated thiatriazinyls are π bonded. [ABSTRACT FROM AUTHOR]

• New magnetic Metal-organic quinoidal polymer Chains are proposed on the basis density functional theory (DFT) calculations. • One-dimensional Metal–Organic Metallic Antiferromagnetic. • Spin-polarized calculations predict the FM semiconducting polymers with a very small energy gap of only 90 meV can be converted to an AFM semiconductor with a large gap of more than 1 eV when oxidized by chlorine. • Band gaps and physical properties of Metal-organic quinoidal polymer suggests their potential candidates for specific applications in Nano electronics and spintronics. We predict two switchable one-dimensional (1D) spin-polarized semiconductors based on metal-organic coordination chains constructed out of Fe, V, and zwitterionic quinone (ZQ) molecules using first-principle density functional theoretical analysis. The Fe-ZQ coordination chain can be converted from a semiconductor to a half-metal when oxidized by chlorine (Cl). Upon chlorination, the magnetic moment of the Fe-ZQ is increased from 4 μ B to 5 μ B , per iron atom. In addition, the bimetallic (Fe-ZQ-V-ZQ) ferromagnetic semiconducting coordination chain with a very small energy gap of only 90 meV can be converted to an antiferromagnetic semiconductor with a large gap of more than 1 eV when oxidized by chlorine. Its magnetic moment is found to be 8 μ B per heterobimetallic unit (Fe and V) after chlorination, and 7 μ B without chlorine. These unique properties, namely a switchable or reversible electronic and magnetic characteristics with a transition between different semiconducting states, make these coordination chains to be highly promising candidates for specific applications as multi-functional switch in nanoelectronics and spintronics. [ABSTRACT FROM AUTHOR]

A remarkable resorcin[4]arene-based [Co 12 ] supermolecule cage functionalized by bio-inspired [Co 4 O 4 ] cubanes was applied as an efficient visible light-driven water oxidation catalyst. [Display omitted] • 1 and 1-a assembled with two bio-inspired [Co 4 O 4 ] cubanes were synthesized. • 1 and 1-a feature efficient photocatalytic water oxidation activity under visible light irradiation. • The density functional theory (DFT) calculations demonstrate the high water oxidation activity of the [Co 4 O 4 ] cubanes in 1. The design and assembly of efficient water oxidation catalysts (WOCs) is quite desirable, but still remains a synthetic challenge. Herein, we researched remarkable calix[4]resorcinarene-based [Co 12 ] coordination cages with bio-inspired [Co 4 O 4 ] cubanes. Markedly, the coordination cage features efficient visible light-driven water oxidation activity, and represents a unique example of calix[4]resorcinarene-based [Co 4 O 4 ] cubane WOC. It afforded an optimal turnover number (TON) of 119, corresponding to a quite high turnover frequency (TOF) of 793 h−1 and an oxygen yield of 17.0%. A possible mechanism for the water oxidation reaction was also proposed by means of density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Reduced dithiolene ligands are bound to high valent Mo centers in the active site of the oxotransferase family of enzymes. Related model complexes have been studied with great insight by Prof. Holm and his colleagues. This study focuses on the other limit of dithiolene chemistry: an investigation of the 2-electron oxidized dithiolene bound to low-valent late transition metal (TM) ions (ZnII, CuI, and CuII). The bonding descriptions of the oxidized dithiolene [ N , N -dimethyl piperazine 2,3-dithione (Me 2 Dt0)] complexes are probed using S K-edge X-ray absorption spectroscopy (XAS) and the results are correlated to density functional theory (DFT) calculations. These experimentally supported calculations are then extended to explain the different geometric structures of the three complexes. The ZnII(Me 2 Dt0) 2 complex has only ligand-ligand repulsion so it is stabilized at the D 2d symmetry limit. The CuI(Me 2 Dt0) 2 complex has additional weak backbonding thus distorts somewhat from D 2d toward D 2h symmetry. The CuII(Me 2 Dt0) 2 complex has a strong σ donor bond that leads to both a large Jahn-Teller stabilization to D 2h and an additional covalent contribution to the geometry. The combined strong stabilization results in the square planar, D 2h structure. This study quantifies the competition between the ligand-ligand repulsion and the change in electronic structures in determining the final geometric structures of the oxidized dithiolene complexes, and provides quantitative insights into the Jahn-Teller stabilization energy and its origin. Among the bis oxidized dithiolene compounds, the ZnII complexe only has ligand-ligand repulsion thus a D 2d geometry. The CuI complex has additional weak backbonding thus distorts from D 2d toward D 2h. The CuII complex has a strong σ donor bonding that leads to both a large Jahn-Teller stabilization to D 2h and an additional covalent contribution to this distortion. [Display omitted] • X-ray absorption spectroscopy (XAS) study of transition metal dithiolene compounds. • Sulfur K-edge XAS and DFT are applied to oxidized dithiolene compounds for the first time. • Electronic structures determine the corresponding geometric structures. • Backbonding in the CuI complexes. • The Jahn-Teller effect and change in covalent bonding in the CuII complexes. [ABSTRACT FROM AUTHOR]

In the ionic structure of the title compound, [Fe(C12H8N2)3](C9H5N4O2)2·H2O, the octahedral tris-chelate [Fe(phen)3]2+ dications [Fe-N = 1.9647 (14)-1.9769 (14) Å; phen is 1,10-phenathroline] afford one-dimensional chains by a series of slipped π-π stacking interactions [centroid-to-centroid distances = 3.792 (3) and 3.939 (3) Å]. The 1,1,3,3-tetracyano-2-(2-hydroxyethyl)propenide anions, denoted tcnoetOH−, reveal an appreciable delocalization of π-electron density, involving the central propenide [C-C = 1.383 (3)-1.401 (2) Å] fragment and four nitrile groups, and this is also supported by density functional theory (DFT) calculations at the B97D/6-311+G(2d,2p) level. Primary noncovalent inter-moiety interactions comprise conventional O-H...O(N) and weak C-H...O(N) hydrogen bonding [O...O(N) = 2.833 (2)-3.289 (5) Å and C...O(N) = 3.132 (2)-3.439 (2) Å]. The double anion...π interaction involving a nitrile group of tcnoetOH− and two cis-positioned pyridine rings (`π-pocket') of [Fe(phen)3]2+ [N...centroid = 3.212 (2) and 3.418 (2) Å] suggest the relevance of anion...π stackings for charge-diffuse polycyanoanions and common M-chelate species. [ABSTRACT FROM AUTHOR]

The title compound, [Zn(SiF6)(C12H8N2)2]·CH3OH, contains a neutral heteroleptic tris-chelate ZnII complex, viz. [Zn(SiF6)(phen)2] (phen is 1,10-phenanthroline), exhibiting approximate molecular C2 point-group symmetry. The ZnII cation adopts a severely distorted octahedral coordination. As far as can be ascertained, the title complex represents the first structurally characterized example of a ZnII complex bearing a bidentate-bound hexafluorosilicate ligand. A density functional theory study of the isolated [Zn(SiF6)(phen)2] complex was undertaken to reveal the influence of crystal packing on the molecular structure of the complex. In the crystal structure, the methanol solvent molecule forms a hydrogen bond to one F atom of the hexafluorosilicate ligand. The hydrogen-bonded assemblies so formed are tightly packed in the crystal, as indicated by a high packing coefficient (74.1%). [ABSTRACT FROM AUTHOR]

Abstract: Apomorphine is a chiral drug molecule; notwithstanding its extraordinary importance, little attention has been paid to the characterization of its chiroptical properties. Here we report on its electronic circular dichroism (ECD) spectra, recorded in methanol and water, and vibrational circular dichroism (VCD) in methanol and dimethyl sulfoxide (DMSO) solutions. Density functional theory (DFT) calculations have allowed us to interpret the spectra and to evaluate the role of possible conformations, charge-states and interactions with counter ions. [Copyright &y& Elsevier]

Atomic sandwich consisting of single atomic layers of Pb and NiSi 2 has been grown on Si(111) and its structural, electronic and transport properties have been elucidated using a set of experimental techniques, scanning tunneling microscopy, angle-resolved photoelectron spectroscopy, in situtransport and magnetotransport measurements, and density functional theory calculations. The Pb layers incorporate around 1.1 monolayers of Pb and display a melt-like 1 × 1 structure at room temperature which crystallizes into the 7 × 7-R38.2 ∘ (i.e., ( 8 3 − 3 5 )) and " 21 × 39 " (i.e., ( 4 − 1 5 7 )) structures upon cooling to low temperatures. Electronic band structure of the Pb/NiSi 2 /Si(111) sandwich contains two bands associated with NiSi 2 and two spin-split bands associated with Pb with minor hybridization of the electrons belonging to different layers. Concerning the transport properties at low temperatures, the sandwich demonstrates a high conductance but without clear indication on superconductivity. [Display omitted] [ABSTRACT FROM AUTHOR]