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Using the principles of density functional theory (DFT) and nonequilibrium Green's function (NEGF), We thoroughly researched carbon-doped zigzag boron nitride nanoribbons (ZBNNRs) to understand their electronic behavior and transport properties. Intriguingly, we discovered that careful doping can transform carbon-doped ZBNNRs into a spintronic nanodevice with distinct transport features. Our model showed a giant magnetoresistance (GMR) up to a whopping 10 5 under mild bias conditions. Plus, we spotted a spin rectifier having a significant rectification ratio (RR) of 10 4 . Our calculated transmission spectra have nicely explained why there's a GMR up to 10 5 for spin-up current at biases of - 1.2 V, - 1.1 V, and - 1.0 V, and also accounted for a GMR up to 10 3 –10 5 for spin-down current at biases of 1.0 V, 1.1 V, and 1.2 V. Similarly, the transmission spectra elucidate that at biases of 1.0 V, 1.1 V, and 1.2 V for spin-up, and at biases of 1.1 V and 1.2 V for spin-down in APMO, the RRs reach 10 4 . Our research shines a light on a promising route to push forward the high-performance spintronics technology of ZBNNRs using carbon atom doping. These insights hint that our models could be game-changers in the sphere of nanoscale spintronic devices. [ABSTRACT FROM AUTHOR]

A series of 4-ferrcenylbutyl carboxylate esters with different alkyl chain length (C2-C4) of carboxylic acids were synthesized using Fe3O4@SiO2@(CH2)3-Im-bisEthylFc[I] nanoparticles as catalyst and have been characterized with FT-IR, 1H NMR, and 13C NMR. Ferrocenyl-based esters were used as corrosion inhibitors of mild steel in the 1M HCl solution as corrosive media. The corrosion inhibition efficiency of the synthesized ferrocenyl-based esters has been assessed by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The 4-ferrocenylbutyl propionate showed a more effective corrosion inhibition behavior among the studied esters with 96% efficiency after immersion in the corrosive media for 2 weeks. The corrosion inhibition mechanism is dominated by formation of passive layer of inhibitor on the surface of the mild steel by adsorption. Moreover, the adsorption characteristics of 4-butylferrcenyl carboxylate esters on mild steel were thoroughly explored using density functional theory calculations. It was found that the Fe atoms located around the C impurity in the mild steel are the most efficient and active sites to adsorb 4-butylferrcenyl carboxylate esters. [ABSTRACT FROM AUTHOR]

This paper provides a critical overview of experimental and computational studies conducted on additive manufacturing (AM) or 3D printing using bimetallic alloys. The review acknowledges the complexity introduced by mechanical interactions and significant interface anisotropies in multi-material AM, making the mechanisms of phase change and microstructure evolution more intricate. Various computational models, such as density functional theory (DFT), phase field, and finite element models, employed in the study of 3D printed bimetallic materials are discussed. The paper highlights the importance of future research in developing quantitative predictions that can simulate and forecast microstructure formation during the AM process. By incorporating computational modeling, this review underlines the potential for overcoming challenges associated with the intricate interactions between different materials in multi-material AM (MMAM). [ABSTRACT FROM AUTHOR]

In women who die from cancer, breast cancer is the most common cause of death. The development of small molecular scaffolds as specific Cyclin-dependent kinase (CDK) inhibitors is a promising strategy in the discovery of anti-breast cancer drugs. Isoindolin-1-ones are heterocyclic compounds with useful therapeutic properties. In this study, a library of 48 isoindolinones has been virtually screened by molecular docking that showed high binding affinity up to − 10.1 kcal/mol and conventional hydrogen bonding interactions with active amino acid residues of CDK7. The molecular dynamics simulation (MDS), fragment molecular orbital (FMO), density functional theory (DFT), and pharmacokinetics studies of the best two docked scored ligands 7 and 14 have been studied. Examining the ligand root mean square deviation and hydrogen bonding occupancy of the 100 ns MDS trajectory, both ligands 7 and 14 showed docked pose stability. FMO calculations displayed that LYS139 and LYS41 are majorly contributing to the binding interactions with ligands 7 and 14 in the docked poses. DFT studies of ligands 7 and 14 showed high values of global softness and low values of global hardness and chemical potential thus displaying chemically reactive soft molecules and this influences their anti-cancer activity. Our hits exhibited superior qualities to known CDK7 inhibitors, according to the comprehensive pharmacokinetic parameters that were predicted. The results indicate that isoindolin-1-one moieties are good candidates for anti-cancer action and could serve as effective CDK7 inhibitors. [ABSTRACT FROM AUTHOR]

Context: Due to the widely known positive contributions of the quinoxaline group in organic semiconductors, we conducted a fully computational study using quantum mechanical methods to investigate the effect of quinoxaline in the electron acceptor unit with the combination of different chalcogen atoms on the band gap of a series of donor–acceptor-donor type conjugated polymers. Using density functional theory, we mainly calculated the electronic band gap values of the structures containing four different chalcogen atoms (O, S, Se, and Te) in the electron donor and acceptor units. While chalcogendiazoloquinoxaline groups were used as the electron acceptor units, furan, thiophene, selenophene, and tellurophene were used as the donor units. Our theoretical results showed that the use of heavy chalcogen atoms in both donor and acceptor units resulted in a low band gap. Besides this, the effect of heavy chalcogen atoms used in the electron donor units is much more pronounced compared to the ones used in the acceptor units. More importantly, our findings proved that the inclusion of the chalcogendiazoloquinoxaline group instead of benzochalcogenadiazole as the acceptor unit significantly decreases the electronic band gap of the conjugated polymer. The lowest band gap was found to be 0.10 eV for the 4,9-di(tellurophen-2-yl)-[1,2,5]telluradiazolo[3,4-g]quinoxaline polymer. Methods: Conformational analysis of the monomers and their corresponding oligomers was performed at the B3LYP/LANL2DZ level of theory. Then, long-range corrected hybrid functional LC-BLYP in a combination with the LANL2DZ basis set was utilized for the calculation of electronic properties and HOMO and LUMO energy gaps of monomers and oligomers through the reoptimization of the lowest energy conformers obtained from the B3LYP/LANL2DZ calculations in the previous step. All energy minimum structures were confirmed through vibrational frequency analysis at both calculation levels. The Gaussian 09 rev. D.01 software was used for all calculations, and GaussView 5.0.9 for visualizations. [ABSTRACT FROM AUTHOR]

Context: By using the DFT theory, the orbital energies of twenty-five ionic liquids were estimated. To comprehend their molecular stability and chemical reactivity, the orbital energy values, orbital energy gap (HOMO–LUMO energy gap), chemical hardness (η), chemical softness (S), electronegativity (χ), and electrophilicity index (ω) were computed. The interaction energies between all of the cations and anions under study were then computed and examined. Finally, using quantum chemical calculations, the molecular polarity of all 25 ionic liquids was examined using the sigma profile and sigma potential. Methods: Using the lowest orbital energy of the molecules, HF/6-31G* level of theory quantum chemical calculation were carried out using the MOLDEN and GAUSSIAN03 software. The B3LYP DFT approach produced a COSMO file that contained the species optimal SCD. [ABSTRACT FROM AUTHOR]

Context: The corrosion of mild steel is a significant issue in various industries, prompting the need for effective corrosion inhibitors. This study focuses on understanding the corrosion inhibition properties of organic compounds derived from isoxazole, namely series Iso(a), Iso(b), Iso(c), Iso(d), Iso(e), Iso(f), Iso(g), and Iso(h), which could have implications for materials science and industrial applications. By investigating the influence of different substitutions on these compounds, valuable insights can be gained into designing better corrosion inhibitors for practical use. Methods: Theoretical studies were conducted using density functional theory (DFT) with the B3LYP functional and the 6-31G (d,p) basis set. These calculations enabled the evaluation of various parameters including frontier orbital energies (EHOMO, ELUMO), energy gap (∆E), electronegativity (χ), absolute hardness (η), softness (σ), fraction of transferred electrons (∆N), as well as local properties such as natural atomic populations and Fukui indices. Additionally, molecular dynamics simulations were performed to study the adsorption behavior of the inhibitors on the surface of Fe (110). The simulations were conducted using Materials Studio version 8.0 software package using COMPASS force field to understand the impact of different functional groups on the inhibitors before and after adsorption on the iron surface. [ABSTRACT FROM AUTHOR]

Context: In the present work, the influence of aromatic ring substitution on a series of small-donor organic molecules (A, B, C, D, and E) with isoxazole cores was investigated for photovoltaic applications in organic solar cells. Frontier molecular orbital analysis, chemical reactivity descriptors, dipole moment, and population analysis showed that all the organic materials have intramolecular charge transfer abilities capable of donating electrons to the acceptor material (PCBM). The required photovoltaic parameters such as Voc, FF, Jsc, LHE, and other associated optoelectronic parameters are reported. The results demonstrate that aromatic ring substitution influences charge transfer and power conversion efficiencies of solar cells. That is, an increase in the aromatic character of a material increases its charge transfer, and as a result, its photovoltaic properties are increased. Additionally, all the investigated derivatives are good charge transporters with suitable electron reorganization energies, which are beneficial for minimizing energy loss. Hence, these organic derivatives with isoxazole backbones are promising materials and may provide fresh insights into the design of new materials for organic solar cell applications. Method: All calculations were performed using DFT and the ORCA 4.1.0 program package as the main tool for geometry optimization and frequency calculations. The Avogadro 1.2.1 visualization tool was used to prepare all input files executed by ORCA 4.1.0. The BP86, B3LYP, and wB97M series of functionals coupled with the def2/TZVP basis set were employed for geometry optimization. All energy-related calculations were carried out using the M06-2x functional. Multiwfn version 3.7 was used for aromaticity and population analysis. Excited state and UV-visible spectra were simulated using the TD-DFT method at the CAM-B3LYP-D3, wB97X-D3, and PBE0-D3 coupled with the ma-def2-TZVP basis set. Moreover, solvent effects were incorporated using the SMD scheme as incorporated in the ORCA software. Lastly, the RIJCOSX approximations were used to speed up calculations while maintaining accuracy. [ABSTRACT FROM AUTHOR]

Context: For the advancement in fields of organic and perovskite solar cells, various techniques of structural alterations are being employed on previously reported chromophores. In this study, the end-capped engineering is carried out on DBT-4F (R) by modifying terminal acceptors to improve optoelectronic and photovoltaic attributes. Seven molecules (AD1-AD7) are modeled using different push–pull acceptors. DFT/B3LYP/6-31G along with its time-dependent approach (TD-DFT) are on a payroll to investigate ground state geometries, absorption maxima (λmax), energy gap (Eg), excitation energy (Ex), internal reorganization energy, light harvesting efficiency (LHE), dielectric constant, open circuit voltage (VOC), fill factor (FF), etc. of OSCs. AD1 displayed the lowest band gap (1.76 eV), highest λmax (876 nm), lowest Ex (1.41 eV), and lowest binding energy (0.21 eV). Among various calculated parameters, all of the sketched molecules demonstrated greater dielectric constant when compared to R. The highest dielectric constant was exhibited by AD3 (56.26). AD5 exhibited maximum LHE (0.9980). Lower reorganization energies demonstrated improved charge mobility. AD5 and AD7 (1.63 and 1.68 eV) have higher values of VOC than R (1.51 eV). All novel molecules having outperforming attributes will be better candidates to enhance the efficacy of OSCs for future use. Methods: Precisely, a DFT and TD-DFT analysis on all of the proposed organic molecules were conducted, using the functional MPW1PW91 at 6-31G (d,p) basis set to examine their optoelectronic aspects, additionally the solvent-state computations were studied with a TD-SCF simulation. For all these simulations, Guassian 09 and GuassView 5.0 were employed. Moreover, the Origin 6.0, Multiwfn 3.8, and PyMOlyze 1.1 software were utilized for the visual depiction of the graphs of absorption, TDM, and DOS, respectively of the studied molecules. A number of crucial aspects such as FMOs, bandgaps, light-harvesting efficiency, electrostatic potential, dipole moment, ionization potential, open-circuit voltage, fill factor, binding energy, interaction coefficient, chemical hardness–softness, and electrophilicity index were also investigated for the studied molecules. [ABSTRACT FROM AUTHOR]

Context: Hydrogen sulfide gas poses significant risks to both human health and the environment, with the potential to induce respiratory and neurological effects, and a heightened fatality risk at elevated concentrations. This article investigates the catalytic decomposition of H2S on a Sc-Ti3C2O2 single-atom catalyst(SAC) using the density functional theory-based first-principles calculation approach. Initially, the adsorption behavior of H2S on Ti3C2O2-MXene was examined, revealing weak physical adsorption between them. Subsequently, the transition metal atom Sc was introduced to the Ti3C2O2 surface, and its stability was studied, demonstrating high stability. Further exploration of H2S adsorption on Sc-Ti3C2O2 revealed direct dissociation of H2S gas molecules into HS* and H*, with HS* binding to Sc and H* binding to O on the Ti3C2O2 surface, resulting in OH groups. Using the transition state search method, the dissociation of H2S molecules on the SAC's surface was investigated, revealing a potential barrier of 2.45 eV for HS* dissociation. This indicates that the H2S molecule can be dissociated into H2 and S with the action of the Sc-Ti3C2O2 SAC. Moreover, the S atom left on the catalyst surface can aggregate to produce elemental S8, desorbing on the catalyst surface, completing the catalytic cycle. Consequently, the Sc-Ti3C2O2 SAC is poised to be an efficient catalyst for the catalytic decomposition of H2S. Methods: The Dmol3 module in Materials Studio software based on density functional theory is used in this study. The generalized gradient approximation method GGA-PBE is used for the exchange–correlation function. The complete LST/QST and the NEB methods in the Dmol3 module were used to study the minimum energy path of the dissociation of hydrogen sulfide molecules on the catalyst surface. [ABSTRACT FROM AUTHOR]

Context: Explosive properties of novel potential high energy density materials of a series of 1,2-diazete-based molecules with trinitromethyl functional group were investigated computationally. All the sixty seven molecules were optimised to obtain their molecular geometries and electronic structures. Electrostatic potential analysis was also carried out in the determination of different parameters. The calculations indicate that the majority of the compounds have high positive heat of formations, high density and good detonation performance greater than that of traditional energetic materials like RDX and HMX. They are also having comparable values of impact sensitivity. These features promise their potential to be used as energetic materials for future applications. Most of the designed molecules are having high positive oxygen balance values so that the study of these molecules can also be extended as potential candidates for oxidisers in solid propellants. Methods: Optimisation and vibrational frequency analysis of the studied molecules were done with density functional theory using B3LYP/aug-cc-pVDZ as the basis set to zero imaginary frequencies using Gaussian 09. Electrostatic potential analysis were carried using the Multiwfn program. [ABSTRACT FROM AUTHOR]

Context: This investigation includes the structural and optoelectronic characteristics of both pure and Er-doped rock salt aluminium nitride (AlN). Upon introducing Er doping into the AlN host, the calculations reveal a rise in the atomic parameter. Incorporating Er into the system leads to enhancements in the static dielectric coefficient ɛ1(0), static reflectivity R(0), as well as static refractive index n(0), at zero frequency. After doping, the peaks of imaginary dielectric tensor, extinction coefficient and absorption coefficient shift towards lower energy levels. Various exchange correlation potentials are incorporated to compare the results of electronic and optical characteristics. Methods: We employed the full potential linearized augmented plane wave (FP-LAPW) approach with WIEN2k code in conjunction with the density functional theory (DFT). To explore the optoelectronic characteristics of both pure as well as doped systems, three distinct exchange correlation potentials are utilized: the Perdew-Burke-Ernzerhof Generalized Gradient Approximation (PBE-GGA), Modified Becke Johnson Generalized Gradient Approximations (mBJ + GGA) and Hubbard potential (GGA + U). [ABSTRACT FROM AUTHOR]

The structure prediction algorithm CALYPSO combined with density functional theory calculations are used to find the high-pressure stable structure of manganese diboride (MnB2) in the pressure range of 0–400 GPa. It is found that the pressure-induced phase transition sequence of MnB2 should be P63/mmc (hP6-MnB2) → Immm (oI18-MnB2) → Pnma (oP12-MnB2) → Imma (oI12-MnB2), and the transition pressure is 35.9, 62.4, and 137.3 GPa, respectively. Among them, oP12-MnB2 is a new stable orthorhombic phase in MnB2 and never have been reported before. At ambient conditions, the calculated hardness of hP6-MnB2 and oI18-MnB2 is 34.5 and 22.9 GPa, respectively, suggesting that they are potentially hard material. However, oP12-MnB2 and oI12-MnB2 just possess a smaller hardness value of 13.9 and 16.2 GPa at the pressure of 80 and 140 GPa, respectively. In addition, the electronic structure and chemical bonds studies showed that the strong covalent bond formed by B-B bonds serve as the primary factor for maintain the structural stability of oP12-MnB2 and oI12-MnB2 under high pressure. Furthermore, at the pressure of 140 GPa, the B-B bonds of oP12 phase exists obvious antibonding characteristics below Femi level. The filling of anti-bonding states is detrimental to the stability of the crystal structure, which is the reason why the oP12 phase is less stable than the oI12 phase at this pressure. [ABSTRACT FROM AUTHOR]

Binary antimonene-phosphorene, a novel 2D semiconductor material, shows potential applications in gas sensing due to its favorable properties. In this work, the sensing properties of binary antimonene-phosphorene nanoribbons by varying the phosphorus mole fraction for the adsorption of NO, CO, NO2, CO2, SO2, SO3, H2S, NH3, O2, and N2 gas molecules are theoretically investigated with first-principles method based on the density function theory. The adsorption distance, adsorption energy, charge transfer, work function, and recovery time of gas molecules adsorbed on the different substrates of phosphorus mole fraction are calculated and compared to evaluate the sensing performance of these structures. The results demonstrate that all the examined gas molecules form stable physisorption with binary nanoribbons (except O2 molecule). Through the analysis of adsorption energy and charge transfer, it can be seen that binary nanoribbons with mole fractions of 25 and 75% have higher selectivity and sensitivity to gas molecules. For example, the charge transfer results show that there is more charge transfer from SO3 (0.456 e) and O2 (0.4 e) gas molecules to 25 and 75% phosphorus substrates than other substrates of mole fraction, respectively. Moreover, for a better comparison, the I–V characteristics of different phosphorus mole fraction are calculated for SO3 and O2 gases. The calculated current–voltage curves confirm the charge transfer results. As a result, our theoretical studies show that binary nanoribbons with some mole fractions can offer promising platform for gas sensing applications. [ABSTRACT FROM AUTHOR]

Dual-atom site catalysts with the adjacent metal atomic sites can cooperatively catalyze oxygen reduction reaction (ORR), showing great potential in ORR field. Herein, the ORR activity and mechanism of a supported metal dual-atom site catalyst M2-DAC (M is 3d transition metal) is explored thoroughly by density functional theory methods. By calculating Ed of M2-DAC, all structures are thermodynamically stable and are used for subsequent studies. Considering the adsorption of O2, total 6 kinds of M2-DAC are identified as potential candidate materials for catalyzing ORR due to their moderate adsorption of O2. The binding energy of ORR species and the change of Gibbs free energy in each step of ORR are calculated, and Co2-DAC exhibits notable catalytic activity (ηORR = 0.39 V). Moreover, the charge analysis of Co2-DAC shows that the ORR activity of the catalyst mainly comes from the metal atom and the O atoms coordinated with the metal atoms. [ABSTRACT FROM AUTHOR]

The structure, hydrogen bonding, and hydrogen transfer of 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) aggregations, including dimer and trimer of carbene(α) and covalent(β) conformation, have been investigated using density functional theory B3LYP together with D3 dispersion correction. The geometrical parameters, Gibbs free energy of formation in gas and solution phases were calculated for aggregates of the complex [Bmim]OH conformation. The strengths and binding energies of different types of H-bonds were predicted by quantum theory of atoms-in-molecules descriptors. The results show that O–H···C hydrogen bonds were formed between most hydroxyl protons and the carbon atom of the carbene ring (C2) in [Bmim]OH aggregations. Furthermore, we examine the proton transfer in dimer and trimer conformation of [Bmim]OH, the reaction pathway for proton transfer from hydroxyl of β-conformer to carbene ring was investigated, and the proton transfer process is energetically favorable. [ABSTRACT FROM AUTHOR]

The present work reports the antitumor activity and a comprehensive study of the Cu(II) complex with 1,10-phenanthroline and l-tyrosine, synthesized by slow solvent evaporation method. X-ray powder diffraction (XRPD) showed that the complex crystallizes in a monoclinic structure with P21/c-space group. All IR- and Raman-active bands were assigned and vibrational properties were evaluated under solvation effects from quantum chemical calculations using density functional theory (DFT). Additionally, optimized geometry, electrostatic potential surface, spatial distribution, and energies of molecular orbitals HOMO and LUMO, as well as chemical reactivity indexes, were obtained using PBE1PBE theoretical level. Antitumor activity of the complex was evaluated through cytotoxic tests in vitro in tumor cell lines PC3 and SNB-19, presenting IC50 equal to 1.5 μM and 2.9 μM, respectively. Additionally, ADME parameters were evaluated to study the drug-like properties of the synthesized complex. Therefore, our findings suggest that the complex presents a promising antitumor activity, with the potential to be used in cancer chemotherapy treatment. [ABSTRACT FROM AUTHOR]

Desulfurization is a necessary process to reduce the corrosiveness of natural gas. In this regard, H2S adsorption on porous materials has gained attention in the development of new eco-friendly technologies. Although there are many experimental and theoretical studies about gas adsorption on MOFs, so far, there has been no theoretical work about desulfurization of natural gas or biogas through H2S adsorption on MOF BTC. Therefore, the objective of this study was to preselect by ab initio calculations which metal center M2+, such as Co2+, Ni2+, Cu2+, or Zn2+, has the highest potential for selective desulfurization of natural gas. DFT calculations were performed at B3LYP-D3/6-311++G(2d,p)+LanL2DZ level for H2O, H2S, COS, CO2, and CH4 adsorption on M-BTC MOF clusters in order to obtain adsorption complex equilibrium geometries, adsorption energies and thermodynamic properties. It was found that Zn-BTC MOF cluster has the highest potential for selective H2S removal from dry natural gas streams, since its adsorption energy is −79.4 kJ mol−1, which is 2.4 times higher than CH4. Furthermore, H2S adsorption on Zn-BTC MOF is an exothermic process and thermodynamically favorable. Through NBO and EDA analyses, it was found that d electrons transfer from adsorbate to metal center unoccupied orbitals contributes mainly to a possible H2S chemisorption on Zn-BTC and Co-BTC, while for CO2 and CH4 adsorption, non-bonded interactions predominate. Most of the gases coordinate to coordinatively unsaturated site of BTC MOF cluster at axial position, indicating a stronger interaction with metal center compared to linkers. [ABSTRACT FROM AUTHOR]

Anodic oxidation is a promising method for removing organic pollutants from water due to its high nonselectivity and effectiveness. Nevertheless, its widespread application is limited due to its low current efficiency, high energy consumption and low treatment rates. These problems may be overcome by the optimization of the process parameters, reactor design and electrode geometry, by coupling the experimental investigations with mathematical modeling. Here we review the modeling of anodic oxidation with focus on basics of this process, the competition phenomenon in real wastewater, flow cells and batch cells, historical aspects, general modeling equations, modeling with plate electrodes, modeling with porous 3-dimension electrodes and the density functional theory. Mathematical modeling can provide current, voltage and concentration distributions in the system. Mathematical modeling can also determine the effects on the performance of parameters such as diffusion layer thickness, flow velocity, applied current density, solution treatment time, initial concentration and diffusion coefficients of organic pollutants, electrode surface area, and oxidation reaction rate constant. Mathematical models allow to determine whether the limiting factor of the process is kinetics or diffusion, and to study the impact of competition of phenomena. The density functional theory provides information on probable reaction pathways and by-products. [ABSTRACT FROM AUTHOR]

The corrosion inhibition of Thymus leptobotrys Murb essential oil (TLMEO) is evaluated for mild steel (M-S) in 1M HCl solution using electrochemical and surface analysis. Results showed that TLMEO acted as a potential corrosion inhibitor and shows the highest inhibition efficiency of 91.7% at 2g/l concentration. Electrochemical studies suggest that TLMEO acted as a mixed- and interface-type of corrosion inhibitor. The TLMEO inhibits metallic corrosion through an adsorption mechanism that follows Langmuir's adsorption isotherm model. The adsorption mechanism of corrosion inhibition was further supported using SEM–EDX, and surface studies. In addition, the anti-corrosion mechanism of the main TLMEO compounds was studied using computational techniques: Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations. Theoretical results were consistent with the experimental findings that were reported. [ABSTRACT FROM AUTHOR]

Finding cost-effective and sustainable methods for the removal of hydrogen sulfide (H2S), a highly toxic gas released as a byproduct in many industrial activities, is crucial for environmental health. In this study, the adsorption and electronic sensor properties of Ti, V, Cr and Sc doped graphene nanosheets (GN) for H2S molecule have been investigated using Density Functional Theory (DFT) method. The WB97XD method with 6-31G(d,p)/LanL2DZ basis sets have been utilized in DFT calculations. The charge distribution indicates that the charge transfer occurred between metal doped graphenes and H2S. DFT calculations of H2S molecule adsorption on Ti, V, Cr and Sc doped graphenes demonstrate that the ability to adsorb H2S molecule. The obtained adsorption energy (∆E) values vary in the range of -54.4 to -71.0 kJ/mol. Furthermore, the electrical conductivity of the Cr doped graphene nanosheet (Cr-GN) changed due to the change in the HOMO–LUMO gap (∆Eg = 24.8 kJ/mol). This result indicates that the Cr-GN structure is a potential candidate as an electronic sensor for H2S molecule at room temperature. Through methods like DFT, which are cost-effective and highly compatible with experimental results, predicting suitable adsorbents, understanding their properties, and enhancing them are expected to make substantial contributions to the industrial-scale production of these materials in terms of cost and accuracy in the future. [ABSTRACT FROM AUTHOR]

Herein, the structural evolution, electronic and magnetic properties of CrSin−/0 for n = 19–25 have been investigated at density functional theory (DFT) level. The global minimum structures of these clusters have been fully searched through a self-developed genetic algorithm code combined with DFT calculations. Both of anionic and neutral CrSin for n = 19–25 share the same configurations. All these clusters prefer to adopt endohedral structures (Cr@Si14 for sizes n = 19–21, and Cr@Si13 for larger ones) as the structural motif with the remaining Si atoms attached on the surface. Among all these clusters, CrSi22 and CrSi23 are the most prominent through the analysis of HOMO − LUMO gaps, average binding energies, and the second order of energy differences. All of these medium-sized cluster anions possess the same total magnetic moment of 1 μB, but with very different contributions from that of small sizes (n ≤ 18), except for size 22. [ABSTRACT FROM AUTHOR]

The molecular and high-energy density properties of isolated (3,4-dinitropyrazole, 34DNP) and fused pyrazole ring (1H,4H-3,6-dinitropyrazolo[4,3-c]pyrazole, DNPP) systems were studied by density functional theory (DFT) at the B3LYP/G D3BJ level of theory with def2-TZVP basis set. The theoretically optimized geometrical parameters of both molecules are similar to the corresponding experimental geometrical values. With this, atoms in molecules (AIM), electrostatic, intrinsic bond strength index (IBSI), and natural bond orbital (NBO) properties of the 34DNP and DNPP molecules were studied. These studies show that one of the nitro groups in 34DNP is less stable than other nitro groups present in 34DNP and DNPP molecules. The optimized geometry, AIM analysis, and NBO results confirmed that one of the C-NO2 groups in isolated dinitropyrazole 34DNP makes fewer orbital interactions with the pyrazole ring, and deviation in planarity leads to relatively less stability and acetic than the fused dinitropyrazole DNPP molecule. These studies reveal that the effect of ring fusion in dinitropyrazole derivatives may be used to design high-quality high-energy density materials. [ABSTRACT FROM AUTHOR]

Photocatalytic processes are able to decompose dyes and toxic substances in the water environment. This fascinating topic can address many environmental concerns about polluted water. Zinc oxide is widely used as a photocatalyst in various nanocomposites. In this study, the formation of a nanostructure including cyclodextrin and ZnO has been investigated by density functional theory (DFT) in gas and aqueous phases at B3LYP and M06-2X functional levels. The calculated binding energies and natural bond orbital (NBO) analysis indicate the existence of strong chemical interactions of ZnO with the inside of the cyclodextrin (CD) cavity during CD-ZnO formation. In addition, the interaction of methylene blue (MB) and phenol red (PhR) dyes with CD-ZnO nanostructure has been investigated. The dyes' adsorption energy values on the CD-ZnO ranged from − 243.4 to − 55.9 kJ. These energies and the density of states diagrams in their complexes confirm the strong interaction of MB and PhR with CD-ZnO. This strong interaction of dyes with nanostructure can support the mechanisms that lead to the photocatalytic degradation of dye molecules. [ABSTRACT FROM AUTHOR]

New 2,6-bis(1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl)pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone (2Tris@PMDA) and its polymeric hybrids with Anderson polyoxometalates (DiTA@PMDA) and with Lindquist polyoxometalates (DiTL@PMDA) have been synthesized and thoroughly characterized. Using dr. Blade's approach, TiO2 based thin films of 2Tris@PMDA, DiTA@PMDA, and DiTL@PMDA have been designed to explore the adsorption study, optical activity, and photocurrent generation. The calculated electrical conductivity values for 2Tris@PMDA, DiTA@PMDA and DiTL@PMDA were 2.8 × 103 S/m−1.90 × 103 S/m, 2.7 × 103 S/m−1.7 × 103 S/m, and 2 × 103 S/m−1.65 ×103 S/m, respectively. Furthermore, computational analysis for 2Tris@PMDA, DiTA@PMDA, and DiTL@PMDA has been studied at B3LYP using 6-31 G (d, p) and LanL2DZ level of density functional theory. It indicates that the conjugation of 2Tris@PMDA with polyoxometalates makes them a suitable candidate for dye sensitized solar cell due to the charge transfer process in DiTA@PMDA and DiTL@PMDA. [ABSTRACT FROM AUTHOR]

This research work's central focus is synthesizing a novel hybrid compound, formulated as [C6H9N2]2Sb2Cl8. This compound was prepared using the slow evaporation method and confirmed through single-crystal X-ray diffraction at 293 K. It crystallizes in the triclinic system with the centrosymmetric space group P 1 ¯ symmetry, and its unit cell (Z = 2). The intermolecular interactions have been studied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing that the Cl–H contacts contribute the most to the surface area (63.6%). Computational studies that include geometry optimization and harmonic vibrational frequencies were performed using B3LYP method with GENECP set. Acceptable consistency was observed between calculated and experimental results. The assignment of wavenumbers was based on potential energy distribution (PED) using Vibrational Energy Distribution Analysis (VEDA) software. The optical band gap determined by UV–Visible spectroscopy is 3.48 eV for a direct allowed transition. Impedance spectroscopy was performed over a temperature range of 313 K to 413 K and a frequency range of 0.1 Hz to 1 MHz. The Nyquist plots indicated the presence of grain contributions. The conductivity study revealed that the synthesized material exhibits semiconductor behavior. A thermally activated conduction process was identified through the study of alternating conductivity, with a calculated activation energy of 1.104 eV. Additionally, the title compound exhibits a negative temperature coefficient of resistivity (TCR) with value of − 13%, suggesting the suitability of the sample for IR radiation detection applications. [ABSTRACT FROM AUTHOR]

The development of phosphors for warm white light plays a decisive role in the quest for energy-efficient and environmentally friendly lighting technologies. Lanthanide-based phosphors, especially those containing europium ions (Eu3+), offer promising possibilities as they can emit light in the entire visible spectrum. In this study, the luminescence properties of two Eu3+ complexes, specifically [Eucy1a] and [Eu2cy2], synthesized with macrocyclic ligands are presented. The macrocyclic ligands (cy1a)H3 and (cy2)H6 provide a stable coordination environment that allows fine-tuning of photophysical properties, which are crucial for warm white phosphors. Synthesis, molecular modeling using density functional theory (DFT) and spectroscopic characterization of the complexes were performed. Notably, the complexes showed an inefficient energy transfer from the ligands to the Eu3+ ions, resulting in a broad blue emission spectrum corresponding to the ligand emission and the red 4f–4f transitions of Eu3+,which is important for the generation of white light. Photometric evaluation revealed favorable properties, including correlated color temperatures (CCT) indicative of warm white light, high color rendering index (CRI) values and exceptional Luminous Efficacy of Radiation (LER). In addition, the presence of coordinated water molecules influenced the luminescence lifetime and quantum efficiency of the complexes. Overall, the synthesized Eu3+ complexes show promising prospects for applications in solid-state lighting, LED designs and emergency technologies that offer high performance and energy efficiency. [ABSTRACT FROM AUTHOR]

This study conducts a comprehensive investigation into the electronic characteristics and optical behaviour of hetero-ring doped graphene quantum dots (GQDs) using a combination of density functional theory and many-body perturbation methods. The focus is on exploring a novel doping mechanism involving the interplay between the type and positioning of dopant rings, specifically Morpholone, Oxazole, and Thiazole rings. The doping process significantly alters the structural, electronic, and optical properties of the pristine GQD. Structural distortions are observed in the doped nanostructures due to variations in atomic radii and electronegativity among C, O, N, and S atoms. The HOMO-LUMO (H–L) band gap and optical gap exhibit reduction upon doping. Additionally, the absorption spectra of the doped nanostructures shift to lower energy levels compared to the pristine GQD. This finding, coupled with high binding energies and reduced singlet-triplet splitting, provide insights into the photophysical processes within each studied structure, suggesting potential applications. [ABSTRACT FROM AUTHOR]

The pursuit of new materials with tailored properties is essential for advancing technology. This research focuses on GaXF3 (X = Se, Si) fluoroperovskites, utilizing the density functional theory approach. The study begins by assessing structural properties, revealing stable configurations for both compounds. The results from phonon calculations confirm the thermodynamic stability of the compounds. The relationship between elastic constants, confirms their mechanical stability. Elasticity analysis using the IRelast package indicates their resilience, anisotropic characteristics, and mechanical stability. Electronic properties, including band structure, density of states, and electronic band gaps, show that both materials have a metallic nature. Additionally, optical properties, such as dielectric constants, absorption coefficients, and refractive indices, are explored, providing insights into their interactions with light for optoelectronic applications. Optical property calculations for both GaSeF3 and GaSiF3, indicate their potential suitability for use in optoelectronic devices, particularly LEDs, due to their absorption within the UV–Vis range. These results encompass properties such as reflectivity, refractive index, and absorption coefficients, indicating their relevance to potential applications in optoelectronic devices. These findings enhance our understanding of these materials and lay the groundwork for future advancements in advanced materials science. [ABSTRACT FROM AUTHOR]

First principles calculations of the structural, electronic and optical properties of GaSb, InSb and their ternary Ga 1 - x In x Sb alloys (x = 0.25, 0.50 and 0.75) have been performed using the full-potential linear muffin-tin orbital (FP-LAPW) method within density functional theory (DFT). The generalized gradient approximation and modified Becke and Janson functional with local density approximation (mBJ–LDA) are utilized for the treatment of exchange and correlation potentials. The results show the calculated lattice constants increase linearity with increasing the In concentration. The electronic band structure indicates that these alloys are direct band gap semiconductors for all the values of x and the band gap decreases as x increases from x = 0 to x = 1. The results also show that the there is a non-linear dependence of the band gap on composition x in Ga 1 - x In x Sb alloys. Regarding optical properties, the real and imaginary parts of the dielectric function have been calculated. The results show that the static dielectric constant increases with increase in concentration of In, consistent with reduction in energy band gap. The onset point and major peaks in the imaginary parts of the dielectric function spectra are identified for the Ga 1 - x In x Sb alloys and shown that they are related to the corresponding band gap values. The results also show that for energy values higher than ≅ 4 eV, the electromagnetic wave transition through Ga 1 - x In x Sb alloys is nearly zero. [ABSTRACT FROM AUTHOR]

Hole transport materials (HTMs) are indispensable for achieving high-performance perovskite optoelectronic devices. We have designed hole transport layer materials, and the geometries, electronic properties, excited state properties, and carrier mobilities of the promising experimental HTM molecule PCA-2 and designed molecules based on PCA-2 by substituting the core structures (named DMS, DMC, DMN and DMO) have been theoretically investigated by employing quantum chemistry methods. Our results show that all the HTMs exhibit excellent planarity and light absorption properties, which are beneficial for facilitating intramolecular charge transfer and enhancing device short-circuit current. The stability of all the studied HTMs was better than that of Spiro-OMeTAD. Additionally, the designed molecules exhibit good capability of hole injection, with DMC, DMN and DMO also displaying effective electron-blocking ability. The solubility of DMN surpasses that of all other molecules. Among the designed HTMs, the hole mobilities of all HTMs except for DMC, are improved compared with the experimental molecule PCA-2. Notably, DMN not only exhibits energy levels matching with perovskite but also has the largest hole mobility, which gives it the potential to be an ideal HTM. This comprehensive study will provide insights into charge transport materials for perovskite optoelectronic devices. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrogen reduction reaction (NRR) is a promising technology for ammonia synthesis under environmental conditions due to its simplicity of operation, high energy conversion, and environmental friendliness. While development of an efficient and stable electrocatalyst is one of the remaining key challenges. In this paper, the electrocatalytic performance of single Ru atoms anchored in Bn-doped graphyne (RuBn@GY) is systematically investigated using density functional theory (DFT) calculations. The results show that RuB@GY is a highly efficient NRR electrocatalyst with a distal and alternating mechanism considered to be the most active catalytic pathway, with a limiting potential of only − 0.53 V. Overall, our study facilitates the NRR reaction by controlling the number and position of the doped B atoms to reduce the limiting potential, and this work provides theoretical guidance for the further development of highly active and stable single-atom catalysts (SACs). Electrocatalytic nitrogen reduction reaction (NRR) is a promising technology for ammonia synthesis under environmental conditions due to its simplicity of operation, high energy conversion, and environmental friendliness. [ABSTRACT FROM AUTHOR]

We studied the impact of dopants Al, Ga and In atoms on the dacarbazine (DAC) drug delivery performance of a BC3 nanosheet (BCNS) using the density functionals τ-HCTHhyb, M06-2X and B3LYP. It was found that the pristine BCNS is not a good choice for this drug delivery. Doping of the Al, Ga and In atoms into the BCNS surface raised the energy of adsorption of DAC from −6.7 to −26.4, −27.8 and −32.1 kcal / mol, respectively. According to the analysis of the partial density of states, the dopant atoms considerably contributed to the generation of virtual orbitals of doped BCNS. This showed that the dopants are more suitable for nucleophilic attack than the B atoms. Finally, the adsorption performance and capacity of the DAC are increased by dopants, making the nanosheet more favourable for drug delivery. A drug release mechanism was introduced in cancerous tissues, showing substantial protonation of the DAC in cancerous cells with low pH, leading to the separation of DAC from the sheet surface. The reaction mechanism of DAC with the BCNS changed from covalent bonding in the natural environment to H-bonding in the acidic environment of the cancer tissues. [ABSTRACT FROM AUTHOR]

Density Functional Theory (DFT) suffers from a strong dichotomy between accuracy and consistency. There exists a paucity of a generic linear route to the systematic improvement of computed results. Benchmark studies are often unidimensional and based on molecular/atomic properties that contour on a single Potential Energy Surface. Thus, the DFT functionals so developed and optimized to similar chemical accuracy lack a universal adherence to the unique density distribution for a fixed nuclear arrangement. We have identified this as a major source of inconsistency within the DFT framework and have explored through the cross-correlations between Structure, Energy, and Dipolar Strength. Since Range Separated Hybrid (RSH) functionals are well-known in literature to produce one of the finest molecular structures in both ground and excited states, in this communication, we have utilized CAM-B3LYP, LC- ω HPBE, and ω -B97XD to explore the above cross-correlations on well-studied test subjects comprising of Anthracene, Tetracene, Phenanthrene and Pyrene in all possible combination of these functionals. The combined responses from the functionals have revealed that major inconsistency operating between structure and energy dictates the variations in the dipolar strength and that lower RMSD and higher charge reorganization are the keys to higher dipolar strength. While LC- ω HPBE stands out, CAM-B3LYP and ω B97XD remain comparatively more like each other except in the Adiabatic Energy Difference (AED) trend. [ABSTRACT FROM AUTHOR]

The quantitative structure-property relationship (QSPR) technique is used to gauge the n-octanol/water partition coefficient (log KOW) and enthalpy of vaporization (∆vapHm) of 133 Polychlorinated Biphenyls (PCBs) using conceptual density functional theory (CDFT)-based global reactivity and information-theory (IT) based parameters. Regression models are established using linear and multi-linear relationships to correlate the observed physicochemical properties of PCBs with the predicted ones. The study explored the significance of CDFT and IT descriptors, and based on the calculation of Pearson correlation coefficient values, the selection of suitable descriptors is made for successful QSPR models of selected PCBs. It is found that some of the CDFT parameters are highly correlated with the IT parameters, as suggested by their high Pearson correlation coefficient values for PCB systems. The regression model generated using the descriptors IG, g1, g2, EA, η for predicting log KOW and IF, g3, η, SS, SGBP for predicting ∆vapHm gives R2 value of 0.9342 and 0.8662, respectively, for the selected 133 PCB congeners. Furthermore, to verify the descriptor selection, a machine learning approach is also used to develop QSPR models in this study. QSPR modelling using CDFT and information theory-based descriptors for predicting n-octanol/water partition coefficient and enthalpy of vaporization for the selected PCBs [ABSTRACT FROM AUTHOR]

A new ternary coordination polymer (CP), {[Cd(L)(nip)(H2O)]·H2O}n (1) (L = 1,6-bis(benzimidazol-2-yl)hexane, H2nip = 5-nitroisophthalic acid), was hydrothermally synthesized and characterized. 1 is a two-dimensional sheet and extends into three-dimensional supramolecular networks through O-H···O hydrogen bonding interactions, which displays high thermal and pH stabilities. 1 demonstrated notable selectivity, sensitivity, and reusability for the luminescent sensing of chlortetracycline (CTC) and Fe3+ ions. Density functional theory calculations and UV−Vis absorption spectroscopy were employed to investigate the possible sensing mechanisms. A new Cd(II) metal coordination polymer, namely {[Cd(L)(nip)(H2O)]·H2O}n can act as a sensitive luminescent probe for chlortetracycline (CTC) and Fe3+ ions in water with excellent selectivity and recyclability. [ABSTRACT FROM AUTHOR]

With the aim of studying the electronic and structural properties of metalloporphyrins, we first prepared the 4-acetoxy-3-methoxy benzaldehyde (1) then by reaction this aldehyde with pyrrole the meso-arylporphyrin, namely the meso-tetrakis(4-acetoxy-3-methoxyphenyl)porphyrin (H2TAMPP) (2) was synthesized. We have also prepared a nickel(II) meso-tetra(aryl)porphyrin with the formula [Ni(TAMPP)] (3). Both two porphyrinic compounds 2–3 have been characterized by UV/Vis, fluorescence, 1H and 13C NMR and IR spectroscopies as well as by MALDI and ESI-HRMS mass spectrometry. Density functional Theory (DFT) calculations at the DFT/B3LYP-D3/6–311 G (d, p) level of theory have been carried out to investigate the HOMO–LUMO orbitals of 2–3 and several global reactive parameters of these two compounds such as the chemical potential, the global hardness, the Mulliken electronegativity, the global softness (S) and the global electrophilicity index. The stability and charge delocalization of 2–3 were studied by natural bond orbital (NBO) analysis. On the other hand, our two porphyrinic species 2–3 were theoretically studied for the adsorption of NO2 and H2S gases using the B3LYP/6-31G (d) bases method. Furthermore, H2TAMPP (2) and its corresponding Ni(II) complex (3) were tested as catalysts of the degradation of the methylene blue (MB) and the methyl orange (MO) dyes using an aqueous solution of hydrogen peroxide. [ABSTRACT FROM AUTHOR]

In this study, the electronic transport properties of 11-Cis and Trans retinal, components of rhodopsin, were investigated as optical molecular switches using the nonequilibrium Green's function (NEGF) formalism combined with first-principles density functional theory (DFT). These isomers, which can be reversibly converted into each other, were examined in detail. The structural and spectroscopic properties, including infrared (IR), Raman, nuclear magnetic resonance (NMR), and ultraviolet (UV) spectra, were analyzed using the hybrid B3LYP/6–311 + + G** level of theory. Complete vibrational assignments were performed for both forms utilizing the scaled quantum mechanical force field (SQMFF) methodology. To evaluate the conductivity of these molecules, we utilized current–voltage (I-V) characteristics, transmission spectra, molecular projected self-consistent Hamiltonian (MPSH), HOMO–LUMO gap, and second-order interaction energies (E2). The trendline extrapolation of the current–voltage plots confirmed our findings. We investigated the effect of different electrodes (Ag, Au, Pt) and various connection sites (hollow, top, bridge) on conductivity. The Ag electrode with the hollow site exhibited the highest efficiency. Our results indicate that the Cis form has higher conductivity than the Trans form. [ABSTRACT FROM AUTHOR]

In the present work, four machine learning algorithms back propagation neural network, multilayer perceptron, random forest and support vector regression were employed to predict both the impact sensitivity and electrostatic spark sensitivity of energetic compounds. Based on the density functional theory calculations mainly, there are nine and ten different kinds of descriptors which contain the important parameters related to the molecular composition and structure, the electronic structure, the structural stability and strength, and the energy performance have been selected out to construct the ML models for predicting the impact sensitivity and electrostatic spark sensitivity, respectively. It could be found that selected descriptors are well correlated with the experimental results which have high Pearson's correlation coefficients generally. For the impact sensitivity, the oxygen balance, charge of nitro group, heat of release and self-multiplying coefficient are key descriptors which should be with larger weightiness in the construction of the ML model, while those are the detonation velocity and detonation pressure in the ML of electrostatic spark sensitivity. Based on the analysis and comparing of various parameters for the assessment of ML models, for both the impact sensitivity and electrostatic spark sensitivity, the back propagation neural network model was found to be possess high accuracy and better than other three used models. This work may provide new methods for predicting the sensitivity of energetic compounds and promote the application of machine learning in the field of energetic compounds. [ABSTRACT FROM AUTHOR]

Optoelectronic devices are being extensively employed nowadays that are vital to diverse range of the appliances. The exploration of apposite materials for such efficient devices appears to be challenging. So, this study recommends novel combinations of chalcogenides as high energy materials that are seldom ever described. Here, density function theory (DFT) is employed to analyze the phase stability, optoelectronic, mechanical, thermodynamic, and vibrational properties of tellurium-based ternary chalcogenides XScTe2 (X = Li, Rb) by utilizing Perdew–Burke–Ernzerhof-generalized gradient approximation (PBE-GGA) and HSE06 through CASTEP simulation code. The observed minimum magnitude of free energy for these structures is found to be well-consistent with the stability requirements of the thermodynamics that confirms their chemical stability. The indirect energy band gap declares them semiconductors. Significant absorption is noticed in the ultraviolet (UV) range of the electromagnetic spectrum. The mechanical properties determined through Voigt–Reuss–Hill approximation determine mechanical instability due to the appearance of some negative elastic constants. Pugh's ratios evaluated as larger than 1.75 while demonstrating its ductile nature. The comprehensive analysis of thermodynamic behavior declares that these are thermodynamically stable materials. The density functional perturbation theory (DFPT) delineates no imaginary frequencies signifying both these compounds as stable materials. The thorough examination suffices to identify these materials as effective ones for optoelectronic uses. [ABSTRACT FROM AUTHOR]

In this article, density functional theory (DFT) was applied to research the structures of γ-Fe2O3 and MFe2O4 (M=Co, Cu, Zn) and to optimize the adsorption models of gases such as CO and NO onto the catalysts. Additionally, the study analyzed the CO oxidation reaction on MFe2O4 (M=Co, Cu, Zn) and the selective catalytic reduction (SCR) reaction of CO + NO in CuFe2O4 and ZnFe2O4. Results showed that CO can effectively adsorb on the reactive substrates, reacting with lattice oxygen to produce CO2 and oxygen vacancies during the CO oxidation process. γ-Fe2O3 (001) required an energy of 0.95 eV to complete the reaction, while CuFe2O4 (100) needed only 0.33 eV, offering better selectivity. In the reaction of CO + NO on CuFe2O4 and ZnFe2O4, NO adsorbed on the surface with double oxygen vacancy to form N2O2 intermediate, then reacted to produce N2 and fill the oxygen vacancy. CuFe2O4 and ZnFe2O4 required energy barriers of 0.68 eV and 0.73 eV, respectively, demonstrating the feasibility of the CO-SCR reaction on the catalyst surface. Further exploration of the reaction in an oxygen-enriched environment found that O2 can inhibit the CO-SCR reaction. The study reveals that MFe2O4 (M=Co, Cu, Zn) catalysts can improve the catalytic activity of the CO oxidation reaction and CO-SCR reaction, with CuFe2O4 exhibiting the best selectivity and catalytic activity. What's more, this study also provides insights for the simultaneous removal of CO and NO. [ABSTRACT FROM AUTHOR]

Using scanning tunneling microscopy and spectroscopy we demonstrate a revival of magnetism in 7-armchair nanoribbon by unpassivated atoms at the termini. Namely, a pair of intense Kondo resonances emerges at the peripheries of zigzag terminus revealing the many-body screening effects of local magnetic moments. Although Kondo resonance originates from a missing local orbital, it extends to a distance of 2.5 nm along the edge of the ribbon. The results are complemented by density functional theory calculations which suggest a possible coupling between Kondo states despite screening effects of substrate electrons. These findings indicate a possibility to restore intrinsic magnetic ordering in graphene nanoribbon without major structural modifications. [ABSTRACT FROM AUTHOR]

This study employs ab initio calculations based on density functional theory (DFT) to investigate the structural properties, 1H-NMR spectra, and vibrational spectra of methane sulfonic acid (MSA) at low degree of hydration. The findings reveal that energetically stable structures are formed by small clusters consisting of one or two MSA molecules (m = 1 and 2) and one or two water molecules in (MSA)m·(H2O)n (m = 1–2 and n = 1–5).These stable structures arise from the formation of strong cyclic hydrogen bonds between the proton of the hydroxyl (OH) group in MSA and the water molecules. However, clusters containing three or more water molecules (n > 2) exhibit proton transfer from MSA to water, resulting in the formation of ion-pairs composed of CH3SO3− and H3O+species. The measured 1H-NMR spectra demonstrate the presence of hydrogen-bonded interactions between MSA and water, with a single MSA molecule interacting with water molecules. This interaction model accurately represents the hydrogen bonding network, as supported by the agreement between the experimental and calculated NMR chemical shift results. [ABSTRACT FROM AUTHOR]

In this study, a newly developed composite of biochar-poly(m-phenylenediamine) (BC-PmPD) exhibiting a distinct skeletal structure was synthesized for the purpose of extracting Cr(VI) from aqueous solutions. BC was employed as a supportive carrier onto which PmPD nanoparticles were uniformly affixed through in-situ polymerization and oxidation synthesis, both within and outside the layered configuration of BC. The structural stability and morphologies of BC-PmPD were assessed utilizing Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, thermogravimetric analysis, analysis of specific surface area and pore size, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction. In comparison to other modified BCs reported, BC-PmPD exhibited the highest Cr(VI) removal rate. Specifically, at 303 K, BC-PmPD achieved a maximum Cr(VI) removal capacity of 775 mg g−1, surpassing the capabilities of unmodified BC and PmPD by 10.4 and 2.13 times, respectively. Analyses involving XPS, FTIR, and density functional theory calculation confirmed that proton transfer happened between protonated amine (−NH2) functional group within the structure of BC-PmPD and HCrO4− before the formation of hydrogen bond. Subsequently, environmentally persistent free radicals facilitated the reduction of the adsorbed Cr(VI). Quantification of the functional groups indicated that the amino group was responsible for 93.0% of the Cr(VI) adsorption in BC-PmPD. BC-PmPD displayed potent adsorption and reduction capabilities, alongside notable stability, repeatability, and promising potential for application in the remediation for high concentrations of Cr(VI) in electroplating wastewater scenarios. Highlights: Novel 3D material was prepared and the removal rate of Cr(VI) on BC-PmPD was the highest as compared to reported BCs. The maximum adsorption amount of Cr(VI) on BC-PmPD was high up to 1034 mg g−1 at 323 K and −NH2 adsorbed 93.0% HCrO4–. DFT calculation confirmed proton transfer happened between protonated −NH2 and HCrO4− before the formation of H bond. [ABSTRACT FROM AUTHOR]

In this study, Erdos (ED) high sulfur coal was selected to investigate the sulfur fixation effect of copper oxide (CuO) on H2S, SO2, COS and sulfur-containing radicals formed during pyrolysis by the gas chromatography (Py-GC) and XPS combined with density functional theory (DFT) calculations. By Py-GC analysis, H2S, COS and SO2 release of ED coal significantly decrease after adding 6% CuO, illustrating CuO can adsorb sulfur-containing radicals and prohibit the generation of these three sulfur-containing gases. The adsorption mechanisms of sulfur-containing radicals produced during coal pyrolysis on different CuO surfaces were investigated by DFT calculations. After optimization, the multi-adsorption configurations of ·S·, ·SH and ·S–S· on different CuO (111, O-terminated 110 and Cu-terminated 110) surfaces can be obtained. According to their highest absolute adsorption energies, the O-terminated CuO (110) surface is more favorable for ·S· and ·SH adsorption rather than other two surfaces, while the Cu-terminated CuO (110) surface for the adsorption of ·S–S· and the co-adsorption of ·S·, ·SH and ·S–S· during coal pyrolysis. Furthermore, ·SH is easily dissociated on the O-terminated CuO (110) surface. The S atoms of ·S· and ·SH are bonded with two Cusuf atoms, and every S atom of ·S–S· combines with one Cusuf on the Cu-terminated CuO (110) surface, leading to the generation of two substances similar to Cu2S and sulfide during co-adsorption. This is very consistent with the apparent appearing peak of Cu2S and remaining peak of sulfide in XPS spectra of CuO-ED char. Thus, these DFT theoretical calculations can testify the experimental results of CuO inhibiting H2S, COS and SO2 to release. [ABSTRACT FROM AUTHOR]

Sequencing the DNA nucleobases is essential in the diagnosis and treatment of many diseases related to human genes. In this article, the encapsulation of DNA nucleobases with some of the important synthesized chiral (7, 6), (8, 6), and (10, 8) carbon nanotubes were investigated. The structures were modeled by applying density functional theory based on tight binding method (DFTB) by considering semi-empirical basis sets. Encapsulating DNA nucleobases on the inside of CNTs caused changes in the electronic properties of the selected chiral CNTs. The results confirmed that van der Waals (vdW) interactions, π-orbitals interactions, non-bonded electron pairs, and the presence of high electronegative atoms are the key factors for these changes. The result of electronic parameters showed that among the CNTs, CNT (8, 6) is a suitable choice in sequencing guanine (G) and cytosine (C) DNA nucleobases. However, they are not able to sequence adenine (A) and thymine (T). According to the band gap energy engineering approach and absorption energy, the presence of G and C DNA nucleobases decreased the band gap energy of CNTs. Hence selected CNTs suggested as biosensor substrates for sequencing G and C DNA nucleobases. [ABSTRACT FROM AUTHOR]

A biradical formed by coordination of the organogold derivative of a nitronyl nitroxide radical with 1,1′-bis(diphenylphosphino)ferrocene was obtained. According to X-ray diffraction data, the Au—Au distance in the biradical structure is short (3.372 Å). The O atoms of paramagnetic groups form short intramolecular contacts with H atoms of cyclopentadienyl anions (2.360 and 2.581 Å) and with methyl H atoms (2.280 and 2.525 Å), as well as intermolecular contacts with H atoms of methyl groups (2.462 and 2.610 Å). Using cyclic voltammetry, it was established that the oxidation of the biradical occurs reversibly in three stages at potentials equal to −34, 232, and 845 mV vs. Ag/AgCl. Density functional calculations and the QTAIM and NBO analyses revealed that there is a weak noncovalent bond between gold atoms in the biradical complex due to partial transfer of an electron from the 5d orbital of one AuI ion to the 6s orbital of the other AuI ion. A weak intramolecular antiferromagnetic exchange interaction (J/kB ≈ −20 K) in the crystal structure was predicted. [ABSTRACT FROM AUTHOR]

The reaction mechanism of the Dakin reaction for three lignin model compounds was thoroughly investigated using density functional theory (DFT). A more comprehensive atomic and molecular level oxidation mechanism for the Dakin reaction was proposed, complementing the previously reported reaction process. The potential energy surface information for twelve possible channels was obtained at B3LYP/6–311 + G(d,p) level based on the geometry optimization together with the frequency calculation of the stationary points. The influence of substituent effects on the reaction energy barrier of Dakin reaction in lignin model compounds was estimated. The calculated results revealed that the rearrangement reaction of quinone structure primarily involves ring-forming and ring-opening of epoxy group, the ring-forming on O and C of benzene ring and ring-opening on C and C of benzene ring. The energy barriers of Dakin reaction decrease with an increase in the number of methoxy groups in lignin model compounds. Further elucidation of the Dakin reaction mechanism will provide a theoretical foundation for the development of more effective catalytic systems to enhance the valuable utilization of lignin in future applications. [ABSTRACT FROM AUTHOR]

During the dehydration of waterlogged archaeological wood (WAW), shrinkage inevitably occurs due to capillary force and hydrogen bond recombination as WAW loses free and adsorbed water. Existing drying techniques, including solvent displacement, freeze-drying, and supercritical fluid drying, only take effect by reducing or eliminating the surface tension of liquid. Nonetheless, the contribution of hydrogen bond recombination in shrinkage has long been neglected and a countermeasure concerning this problem is needed. In this study, we propose a simple aqueous phenylboronic acid (PBA) treatment that can help improve dimensional stability and reduce hygroscopicity of WAW. Analysis by Fourier transform infrared spectroscopy, density functional theory calculation and dynamic vapour sorption reveal that PBA can incorporate with hydroxyl groups (–OH) on cellulose through coordination and hydrogen bonds, occupy the water-cellulose binding sites, and possibly inhibit the formation of hydrogen bonds between adjacent cellulose chains. [ABSTRACT FROM AUTHOR]

The study of the structure and properties of extractants is of great significance for developing new extractants. For uranium extraction and recovery requirements in spent fuel reprocessing, three kinds of extractants with different ether-oxygen chains, N,N,N'N'-tetraoctyl-3-oxapentanediamide (TODGA), N,N,N'N'-tetraoctyl-3,6-dioxaoctanediamide (TODOODA) and N,N,N'N'-tetraoctyl-3,6,9-trioxaundecanediamide (TOUDA) were synthesized to study the influence of the ether-oxygen chain skeleton on the extraction of uranium from nitrate media. TODOODA shows a good extraction ability for uranyl ions at high nitric acid concentrations. Equimolar series method, FT–IR spectrum and MALDI–TOF–MS spectra indicated that the extracted structure was formed as [UO2NO3·TODGA]NO3, [UO2NO3·TODOODA]NO3 and [UO2NO3·TOUDA]NO3. [ABSTRACT FROM AUTHOR]