Electronic Structure Parameters Research Articles

Preparation, Characterization, In Vitro Biological Evaluation, DFT Calculations, and Molecular Docking Investigations of 1H-Imidazole-2-Carboxylic acid and Histidine-Based Mixed-Ligand Complexes.

Mixed-ligand complexes incorporating 1H-Imidazole-2-Carboxylic acid (IMCA) and Histidine (LHIS) show promise for biomedical and biotechnological applications. This study synthesizes and characterizes FeIMCALHIS, CoIMCALHIS, and NiIMCALHIS coordination compounds using metal chloride salts (FeCl3.6H2O, CoCl2.6H2O, NiCl2.6H2O) in ethanolic solutions. The complexes are characterized by spectroscopic methods (IR, UV-vis, and mass spectra), elemental analysis, conductivity, magnetic, and thermal analysis. Molar conductivity indicates their non-electrolytic nature. UV-vis spectra reveal absorption bands with pathochromic shifts, and electronic spectra show characteristic metal-ligand transitions, indicating their structural configuration and coordination geometry. 3D geometry optimization shows six-coordination around Fe(III) and Co(II) in FeIMCALHIS and CoIMCALHIS, and four-coordination around Ni(II) in NiIMCALHIS. Analysis of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) suggests decreased electron donation ability upon coordination. Electronic structure parameters (HOMO, LUMO, ionization potential, energy gap, electron affinity, chemical potentials, and electronegativity) provide further insights into stability and reactivity. The metal complexes exhibit enhanced antimicrobial, antioxidant, and anti-inflammatory activity compared to individual ligands, with FeIMCALHIS showing notable antimicrobial activity. Molecular docking analysis reveals strong binding interactions with target proteins, highlighting their potential therapeutic applications.

Theoretical study of optoelectronic, elastic and mechanical properties of gallium modified barium titanate (Ba1-xGaxTiO3) perovskite ceramics by DFT

In this report, we study the gallium modified Barium titanate (Ga-BTO) Ba1-xGaxTiO3 with (x = 50 %) perovskite ceramics, which have not been synthesized experimentally to date. The density functional theory-based full potential linear augmented plane wave has been employed to determine the optoelectronic, elastic, and mechanical properties of pure and modified BaTiO3. Completely relaxed 2 × 2× 2 of primitive five atoms’ cells has been used for calculations. A large cut-off energy of 120 Ry has been used to eliminate the basics of plane wave-indicating wave functions. The influence of substitution of Ga on electronic structure and optical parameters such as reflectivity, refractivity, dielectric function, optical conductivity, extinction, and absorption coefficients are analyzed and elucidated with TDOS and PDOS. The Ga modified BTO manifests a forbidden energy gap of 1.84 eV. The static dielectric constant Ɛ1(o) has values of 8.8 and 100 for pure and modified compounds respectively. Ga dopant improved the polarizing power of BTO and for the doped BTO imaginary part, Ɛ2(ω)showed a prominent peak located at 3.9 eV. The optical properties show that perovskite compound substituted with Ga is a good absorber in the ultraviolet region and the modified material has a small value of reflectivity and static refractive index 12.2. The general profiles of optical spectra of modified BaTiO3 display highly desirable features like the prominent peaks of optical conductivity obtained at 4.2 and 5.8 eV for modified BTO that make it a promising candidate for optoelectronic and spintronics. Ga-modified BTO has higher ductility, modulus (169.96 GPa), and anisotropy (2.949) than pure BTO found by analyzing their elastic and mechanical properties.

Sulfur Modified Carbon-Based Single-Atom Catalysts for Electrocatalytic Reactions.

Efficient and sustainable energy development is a powerful tool for addressing the energy and environmental crises. Single-atom catalysts (SACs) have received high attention for their extremely high atom utilization efficiency and excellent catalytic activity, and have broad application prospects in energy development and chemical production. M-N4 is an active center model with clear catalytic activity, but its catalytic properties such as catalytic activity, selectivity, and durability need to be further improved. Adjustment of the coordination environment of the central metal by incorporating heteroatoms (e.g., sulfur) is an effective and feasible modification method. This paper describes the precise synthetic methods for introducing sulfur atoms into M-N4 and controlling whether they are directly coordinated with the central metal to form a specific coordination configuration, the application of sulfur-doped carbon-based single-atom catalysts in electrocatalytic reactions such as ORR, CO2RR, HER, OER, and other electrocatalytic reaction are systematically reviewed. Meanwhile, the effect of the tuning of the electronic structure and ligand configuration parameters of the active center due to doped sulfur atoms with the improvement of catalytic performance is introduced by combining different characterization and testing methods. Finally, several opinions on development of sulfur-doped carbon-based SACs are put forward.

Optoelectronic and mechanical properties of gallium arsenide alloys: Based on density functional theory

First principles calculations based on density functional theory (DFT) were performed to investigate the structural, electronic, optical and mechanical properties of pristine GaAs compound and its alloy; Ga0.75Al0.25As, Ga0.75In0.25As, Ga0.75Sn0.25As, Ga0.75Ti0.25As. WIEN2K and Quantum expresso (QE) codes were adopted for calculations using generalized gradient approximation (GGA) in Perdew-Burke Erzenhoff (PBE) as exchange correlation function for both codes. Full potential linear augmented plane wave (FPLAPW) with the local orbital method was adopted as implement in WIEN2K code. In QE code, norm-conserving pseudopotentials were employed on a plane-wave expansion of the wave functions. Structural and electronic properties were elaborated since their result gives information about the optical and mechanical performance. Electronic band structure and optical parameters were performed using WIEN2K code. Underestimation of band gap observed from DFT calculations were corrected by using Modified Becke and Johnson (mBJ). Mechanical components were determined using QE with thermo_pw package. Lattice constant, volume, bulk modulus and other physical parameters were calculated for structural properties. Discrepancy in these parameters as observed in crystal structure is associated to difference in ionic radius of host and substituted atom. The results of band structure and density of states were calculated for electronic properties. All the studied compounds were semiconductors in nature except Ga0.75Sn0.25As which displayed metallic character. Optical parameters including extinction coefficient, absorption coefficient, refractive index, optical conductivity, optical reflectivity and energy loss function have been computed from the dielectric function at energy range of 0 to 25 eV using the Kramers-Kronig transformations. Calculated elastic function were used to compute the mechanical properties such as anisotropic, brittle characteristics, stiffness and many others. All the results were compared with available theoretical and experimental records.

Synthesis and performance of a nanosensing platform for homocysteine detection: A series of iridium(III) complexes containing aldehyde group as probe and MOF as supporting substrate

The low cost and simple detection method for Hcy (homocysteine) is highly desired in analytical and biological fields since Hcy has been regarded as a bio-marker for multiple diseases. In this work, five Ir(C^N)2(N^N)+ compounds having –CHO group in their C^N or N^N ligand were synthesized and tried for Hcy sensing. Electron-donating groups such as –NH2 and –CH3 were incorporated into the C^N or N^N ligand. Their geometric structure, electronic structure, and optical parameters (with or without Hcy) were analyzed and compared carefully to explore their Hcy sensing potential. The sensing mechanism was revealed by NMR titration and theoretical simulation as a cyclization reaction between the –CHO group and Hcy. The optimal compounds, which showed increased emission quantum yield (2.5-fold) and emission blue-shift (by ∼ 100 nm) upon Hcy, were then covalently grafted into a porous host bio-MOF-1. Linear working plots were fitted, with good selectivity, LOD of 0.15 μM, and response time of 33 s. The novelty of this work was the eye-sensitive emission color change of this nanosensing platform from red (without Hcy) to green (with Hcy).

Strategies for Effective Degradation of Methyl Orange Dye in Aqueous Solution via Electrochemical Treatment with Copper/Graphite Electrodes

This study investigated the electrochemical degradation of methyl orange dye (MO) in aqueous solution using copper/graphite electrodes as anode and cathode respectively. The process parameters such as electrolyte concentrations, current density, pH and temperature were analyzed. The results proved that copper/graphite electrodes were effective for MO degradation and the reaction followed the first-order kinetic model. The degradation efficiency decreased with increasing MO concentration and increased steadily with current density. The pH trend with degradation efficiency was pH 9 (98%) > pH 7 (96%) > pH 3 (77%) after 70 min of electrolysis time, which shows that the alkaline conditions favoured the degradation process. Fourier transform infrared spectroscopy (FTIR) and UV–Vis absorption spectroscopy confirmed the dye degradation process, with the formation of degradation intermediates. The FTIR results revealed that the oxidative degradation of MO may be initiated at the N=N azo bond, which was confirmed by quantum chemical modelling of the electronic structure parameters of MO.

Synthesis of bis-(benzhydryloxy) substituted axially silicon(IV) phthalocyanine: investigation of photophysical, photochemical, and computational electronic properties

Synthesis of axially disubstituted silicon(IV) phthalocyanine bearing benzhydryloxy groups obtained by reaction of SiPcCl2 with diphenylmethanol is reported. Characterization of the compound was performed by 1H and 13C NMR, UV–Vis, mass spectrometry, and FT-IR spectroscopy. Photophysical and photochemical properties were investigated. Fluorescence spectra measurements were performed in DMSO as solvent. A preferred chemical method was used to determine the amount of singlet oxygen production. Optimizations were calculated for the single-molecule Si-Pc with the 6–311 G (d, p) basis set at the B3LYP and B3PW91 levels of density functional theory (DFT). The charge transfer (or) charge delocalization between intramolecular donor–acceptor groups was determined by NBO analysis. Furthermore, molecular electrostatic potential, Fukui functions, electrophilic and nucleophilic character maps were calculated. The electronic structure and energy parameters of the investigated compound were determined to be ΔE calc = 2.19 eV by DFT calculation and ΔE opt = 1.84 by experimental UV spectrum.

Modulating the Electronic Structure of Cobalt in Molecular Catalysts via Coordination Environment Regulation for Highly Efficient Heterogeneous Nitrate Reduction

AbstractAmmonia (NH3) is pivotal in modern industry and represents a promising next‐generation carbon‐free energy carrier. Electrocatalytic nitrate reduction reaction (eNO3RR) presents viable solutions for NH3 production and removal of ambient nitrate pollutants. However, the development of eNO3RR is hindered by lacking the efficient electrocatalysts. To address this challenge, we synthesized a series of macrocyclic molecular catalysts for the heterogeneous eNO3RR. These materials possess different coordination environments around metal centers by surrounding subunits. Consequently, electronic structures of the active centers can be altered, enabling tunable activity towards eNO3RR. Our investigation reveals that metal center with an N2(pyrrole)‐N2(pyridine) configuration demonstrates superior activity over the others and achieves a high NH3 Faradaic efficiency (FE) of over 90 % within the tested range, where the highest FE of approximately 94 % is obtained. Furthermore, it achieves a production rate of 11.28 mg mgcat−1 h−1, and a turnover frequency of up to 3.28 s−1. Further tests disclose that these molecular catalysts with diverse coordination environments showed different magnetic moments. Theoretical calculation results indicate that variated coordination environments can result in a d‐band center variation which eventually affects rate‐determining step energy and calculated magnetic moments, thus establishing a correlation between electronic structure, experimental activity, and computational parameters.

Modulating the Electronic Structure of Cobalt in Molecular Catalysts via Coordination Environment Regulation for Highly Efficient Heterogeneous Nitrate Reduction.

Ammonia (NH3) is pivotal in modern industry and represents a promising next-generation carbon-free energy carrier. Electrocatalytic nitrate reduction reaction (eNO3RR) presents viable solutions for NH3 production and removal of ambient nitrate pollutants. However, the development of eNO3RR is hindered by lacking the efficient electrocatalysts. To address this challenge, we synthesized a series of macrocyclic molecular catalysts for the heterogeneous eNO3RR. These materials possess different coordination environments around metal centers by surrounding subunits. Consequently, electronic structures of the active centers can be altered, enabling tunable activity towards eNO3RR. Our investigation reveals that metal center with an N2(pyrrole)-N2(pyridine) configuration demonstrates superior activity over the others and achieves a high NH3 Faradaic efficiency (FE) of over 90 % within the tested range, where the highest FE of approximately 94 % is obtained. Furthermore, it achieves a production rate of 11.28 mg mgcat -1 h-1, and a turnover frequency of up to 3.28 s-1. Further tests disclose that these molecular catalysts with diverse coordination environments showed different magnetic moments. Theoretical calculation results indicate that variated coordination environments can result in a d-band center variation which eventually affects rate-determining step energy and calculated magnetic moments, thus establishing a correlation between electronic structure, experimental activity, and computational parameters.

Tailoring optical and photocatalytic properties of sulfur-doped boron nitride quantum dots via ligand functionalization

Boron nitride quantum dots (BNQDs) have emerged as promising photocatalysts due to their excellent physicochemical properties. This study investigates strategies to enhance the photocatalytic performance of BNQDs through sulfur-doping (S-BNQDs) and edge-functionalization with ligands (urea, thiourea, p-phenyl-enediamine (PPD)). To analyze the geometry, electronic structure, optical absorption, charge transfer, and photocatalytic parameters of pristine and functionalized S-BNQDs, we performed density functional theory calculations. The results showed that S-doping and ligand functionalization tune the bandgap, band energies, and introduce mid-gap states to facilitate light absorption, charge separation, and optimized energetics for photocatalytic redox reactions. Notably, the PPD ligand induced the most substantial bandgap narrowing and absorption edge red-shift by over 1 electron volt (eV) compared to pristine S-BNQD, significantly expanding light harvesting. Additionally, urea and PPD functionalization increased the charge transfer length by up to 2.5 times, effectively reducing recombination. On the other hand, thiourea functionalization yielded the most favorable electron injection energetics. The energy conversion efficiency followed the order: PPD (15.0%) > thiourea (12.0%) > urea (11.0%) > pristine (10.0%). Moreover, urea functionalization maximized the first-order hyperpolarizability, enhancing light absorption. These findings provide valuable insights into tailoring S-BNQDs through strategic doping and functionalization to develop highly efficient, customized photocatalysts for sustainable applications.

A Computational Quantum Chemical Approach for Surface Assimilation Effects of Well‐Known Voltage Sensitive Potassium Channel Blockers (4‐Aminopyridine and 3,4‐Diaminopyridine) over Carbon Nanotube

AbstractThe compound 3,4‐diaminopyridine (3,4‐AP), a derivative of 4‐aminopyridine (4‐AP), is used in the symptomatic treatment of fatigue in multiple sclerosis as well as Lambert–Eaton myasthenia syndrome whereas the parent compound 4‐AP is used as an acetylcholine‐releasing drug, in serum, saliva, and urine. 4‐AP is an experimental drug that may reduce symptoms in some people with multiple sclerosis, particularly those who are more sensitive to heat. The carbon nanotubes (CNTs) have inside cavity tethering on the surface upon functionalization and adsorption on the walls of CNTs, which provides extra ability to carry pharmaceutical agents through multiple ways. Due to these benefits, this communication will discuss the comparative changes in geometry, electronic properties, and shielding parameters of 4‐AP and 3,4‐AP absorbed C56H16. The DFT/B3LYP/6–31G (d, p) method is used for the first time to report electronic structure and interaction parameters on the CNT surface. The same level theory is used to discuss the thermodynamic stability of CNT‐4‐AP/3,4‐AP. The calculated UV spectra of CNT are compared with UV spectra of CNT‐4‐AP and 3,4‐AP by using the same level theory in a water solvent, which provides a better comprehension of CNT as a drug delivery system after absorption of the 4‐AP and 3,4‐AP in the human body. The nature and strength of interactions have been discussed with the help of AIM analysis, and the frontier orbital highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap, chemical softness, and chemical hardness have been calculated to understand its complete chemical properties. The characters of the frontier molecular orbitals are discussed and analyzed by comparing the DOS spectra of CNT with CNT‐4‐AP/3,4‐AP.

Systematic First-Principles Calculations of Ce3+-Dopant in Garnet-Type Oxide Phosphors

A study of Ce3+-doped oxide phosphors was performed using first-principles calculations based on the relativistic DV-Xα method. In particular, we focused on the Ce3+-doped garnet-type oxides, which have potential applications in solid-state lighting and display devices. The electronic structure and optical properties of the phosphors were analyzed. The energy levels of the Ce3+ ions were affected by the coordination number and the crystal field strength of the surrounding oxygen ions. In addition, the crystal structure of the material had a significant impact on the energy levels of the Ce3+ ions, with different crystal structures leading to different energy levels.The Ce3+ ion is substitutionally incorporated in the garnet lattice, and the 4f electron of Ce3+ plays an important role in the luminescence of the material. The emission wavelengths of the 5d-4f transition energy of Ce3+ can be tailored by varying the crystal structure and the composition. The 5d orbitals of Ce3+ are substantially affected by the crystal field splitting while the amplitude of crystal field splitting (εcfs) is caused by many parameters: coordination number, symmetry of Ce3+ site, and bond lengths between the Ce3+ ion and the oxygen ions (O2-). This study incorporated the following computational conditions: i) lattice relaxation, ii) the choice of the exchange-correlation potential, and iii) Slater’s transition state method. The effects of these conditions were analyzed. In addition, the correlations among physical properties and electronic structure parameters were also investigated in detail.The first-principles calculation results were compared to the experimental data to validate the accuracy of the theoretical models, which showed a good agreement between the experimental and predicted values.

(Invited) Unravelling Structural Implications on Charge Transport Mechanism in Nanostructured Electrode Materials for Energy Storage Devices

The development of new and novel electrode materials for energy storage devices has become the intensive research by the materials science community because of its importance in the portable electronic devices, hybrid electric vehicles and many other applications. Since the discovery by Goodenough and his co-workers on the electrochemical behavior of olivine LiFePO4 (LFP), different theoretical and experimental investigations have been undertaken to optimize it as cathode material in lithium-ion batteries and trying to understand the charge/discharge mechanism. Despite having many fascinating electrochemical properties, the main drawback of LFP lies with its low gravimetric density and poor electrical conductivity (both electronic and ionic) which limits the lithium intercalation/deintercalation rates, and hence the practical specific capacity. Therefore, it becomes necessary to gain the fundamental understanding of electronic structure of the LFP system by adopting appropriate experimental technique. We exploit the combined Mössbauer and X-ray absorption spectroscopy to unravel the electronic structure and local site symmetry of Fe in olivine structured LFP with different crystallite sizes (CS). The lattice parameters are found to contract with decrease in CS monotonously, whereas the electronic structural parameters exhibit two different regions with threshold anomaly around ≈30 nm CS. The 57Fe Mössbauer studies reveal the coexistence of Fe2+ and Fe3+sites and their relative concentration are mainly determined by the CS, which provides the comprehensive insight into the electronic structure of LFP at mesoscopic level. The soft X-ray absorption unravels unequivocally the valance states of Fe 3d electrons in the proximity of Fermi level, which are prone to the local lattice distortion. An obtained spectra fingerprint the effect of CS supplying rich information on valence state of iron, lithium-ion vacancy concentration, covalency and crystal field. The unique structural and electronic properties of the LFP are closely interlinked with changes in the bonding character, which shows the strong dependency on the CS. The evolution of the 3d states is in overall agreement with the local lattice distortion and provides the origin of the size effects on the electronic structure olivine phosphate and other transition metal ion containing materials. We observe polaronic conductivity enhancement of approximately two orders of magnitude at the nanoscale level as compared with its bulk counterpart. The volumetric changes with respect to crystallite size are related to the compressive strain resulting into the improvement in the electronic diffusivity. The nano-crystalline LFP with better kinetics will open the new avenue for its usage as cathode material in rechargeable batteries.

Strengthening effects of Al element on strength and impact toughness in titanium alloy

Pure Ti and binary Ti–6Al alloy have been employed as the investigated targets of our research. The strengthening effects of Al element on strength and impact toughness in titanium alloy were systematically investigated. The experimental results indicated that the addition of Al element significantly improved the tensile strength while deteriorating the plasticity and impact toughness. Analysis of deformation mechanisms indicated that addition of Al element strongly inhibited the dislocation movement and deformation twinning in titanium alloy. The theoretical results demonstrated that the dissolution of Al atoms reset the atomic bond configurations and electronic structures of the α-Ti lattice. Therefore, the lattice resistance to dislocation nucleation and dislocation gliding was significantly improved which led to the strong strengthening effect of Al element in α-Ti. The lattice resistance to the shearing atomic motion of deformation twinning was also improved due to the dissolution of Al atoms. Moreover, the strengthening of Al element was revealed at the electronic level by employing the empirical electron theory (EET) of solids and molecules. The strengthening effects of Al element in titanium was also quantitatively evaluated according to the valence electron structure (VES) parameters. A prediction model for the tensile strength of α-type Ti-xAl alloys was proposed based on the quantitative strengthening of Al element. The high accuracy of the prediction model for strength of Ti-xAl alloy was verified by the average error (3.58%) between the computational strength and experimental results.

Tuning and interpretation of electronic transport properties with

Electronic transport coefficients such as the electrical conductivity, the termo-power, and the charge carrier concentration are routinely measured in a variety of application areas such as electronics or thermoelectric power-generation and cooling. Using fitting procedures, those measurements are used to infer microscopic features of the samples. The code ▪ facilitates the estimation of electronic structure parameters such as the effective masses and band energies improving the current approach by increasing the complexity of the band structure representation. The software is designed with a server-client architecture to enhance performance and scalability. The server is implemented in the Julia programming language. We illustrate the design and the efficiency of the code with selected applications, which are relevant to the optimization of thermoelectric materials. Program summaryProgram Title:▪CPC Library link to program files:https://doi.org/10.17632/494nj6ftbv.1Developer's repository link:https://github.com/marcofornari/etransport.gitLicensing provisions: GPLv3Programming language: Julia, Python.Nature of problem: Electronic transport measurements are routinely used to link the functional properties exploited in electronics and energy sciences applications with the underlying electronic structure of the material under investigation. Experimentalists collect data of derived and integrated physical quantities, from which they estimate properties and parameters, e.g., nature of the conduction mechanisms and effective mass. The interpretation is based on simplistic models that rarely represent the complexity of the band structure. The code ▪ improves the current state of the art and facilitates the estimation of effective masses and energies from experimental measurements of electrical conductivity, Seebeck coefficients, and carrier concentration using a multi-valley anisotropic parabolic band structure as a model for the unknown real band structure. Experimental data can be imported and visualized to facilitate the comparison with theoretical analysis.Solution method: The Boltzmann equation within the relaxation-time approximation is used to compute the electronic transport tensors from the electronic density of states characterized in terms of a set of effective masses tensors mi⁎ and critical energies ϵi. Numerical and analytical techniques are adopted to integrate the Boltzmann equation efficiently. By tuning the features of the density of states, temperature, Fermi level, and the functional expression for the relaxation time, the software streamlines the reconstruction of the underlying electronic properties from experimental data.Additional comments including restrictions and unusual features: The software is designed with a server-client architecture to enhance performance and scalability. The server is implemented in the Julia programming language as a stand-alone library. It performs all the numerical operations to compute the transport tensors from a set of multi-valley parabolic band structures. The client is implemented either as a command-line user interface (CLI) or a graphical user interface (GUI) written in the Python programming language. The communications between the server and clients are handled by a REST API, where the data are exchanged using JSON payloads.

Design, synthesis, in-vitro and in-silico studies of chromone‐isoxazoline conjugates as anti‐bacterial agents

A novel series of chromone-isoxazoline conjugates was successfully synthesized by the O-alkylation and 1,3-dipolar cycloaddition reactions using methyl 7‑hydroxy-4H-chromone-3-carboxylate as starting material. The structures of the synthesized hybrid compounds were determined using spectroscopic techniques, and mass spectrometry. The in-vitro antibacterial activity of the target compounds was tested against four bacterial strains, and it was found that compound 5e was active against the strains B. subtilis and P. mirabilis. Theoretical calculations were made at the B3LYP, HF, and M062X level on a 6–31++g(d,p) basis in order to optimize the geometric structures and calculate the geometric and electronic structure parameters of the target compounds. In addition, molecular docking studies were performed to understand and identify the mode of interaction between the hybrid compound 5e and the bacterial proteins of B. subtilis and P. mirabilis. The outcomes revealed that the hybrid compound 5e displayed strong binding affinities within the target receptors’ active site. Also, a 100 ns molecular dynamics simulation was used to assess the behavior and stability of the complexes formed between ligand 5e and the bacterial receptors. Lastly, in silico ADMET analyses suggest that the target compounds exhibit favorable pharmacokinetic properties, including significant oral bioavailability.

Hyperfine-Resolved Rotational Spectroscopy of Phenyl Radical.

We present an analysis of the hyperfine-resolved rotational spectrum of gas-phase phenyl radical, c-C6H5, between 9 and 35 GHz. The isotropic and anisotropic hyperfine parameters of all five protons and the electronic spin-rotation fine structure parameters are accurately determined from this study, which allow detailed insight into the distribution and interactions of the unpaired electron in this prototypical σ-radical. The implications for laboratory and astronomical investigations of phenyl that are reliant on a precise centimeter-wave catalog are discussed, as are the prospects for detecting and assigning the hyperfine-resolved rotational spectra of other large, weakly polar hydrocarbon chain and ring radicals.

Design and development of salen-type Schiff bases as potential antivirus agents: Experimental and theoretical approach

Five new salen-type Schiff base compounds (LH2-L4H2) have been designed and synthesized and their interaction with SARS-CoV-2, HIV virus and DNA polymerase IV have been studied by in silico approaches. The newly synthesized salen-type Schiff base ligands have been derived from the condensation of substituted salicylaldehydes and ethylenediamine in MeOH. 1H and 13C NMR, FT-IR and UV-Vis spectral techniques have been applied in order to confirm the structural elucidation of the desired products. The crystal structure of the compound LH2 is determined by the single crystal X-ray diffraction. Density functional theory (DFT) calculations have been employed to evaluate the optimized electronic structure, HOMO-LUMO, energy gap, and global parameters. Extensive classical molecular dynamics simulations have been performed to investigate the consequences of docking of the synthesized ligand, LH2 on a protein moiety (PDB id: 7O46). Molecular docking studies have been performed on compounds (LH2-L4H2) to predict the binding mode and interactions between the ligands and the main protease of the SARS-CoV-2 (PDB ID: 7O46) for COVID-19 and HIV virus (PDB ID: 1UUI). The molecular docking results show that compounds (LH2-L4H2) with SARS-CoV-2 and HIV virus exhibit good binding affinity at binding site of receptor protein. As potential drug candidates, Swiss-ADME and target predictions (pharmacokinetics and drug-likeness prediction) analyses have also been studied and the results are compared with Chloroquine (CQ) and Hydroxychloroquine (HCQ) as anti-SARS-CoV-2 drugs. Salen-type ligands have also been docked into the DNA polymerase IV (PDB ID: 5YUX) for surface binding and intercalation. Overall, the present study offers the therapeutic potential for a series of compounds (LH2-L4H2) for biomedical applications with reference to coronavirus (SARS-CoV-2) and HIV virus.

Synthesis and Optoelectronic Features of Rhodamine-Triazole Dyads as Metallochromic Probes for Copper-Selective Chemosensing.

Rhodamine-based chromic materials have attracted significant interest owing to their cation recognition ability with high sensitivity. However, rhodamine chromophores with controllable sensing selectivity towards transition metal species are only at the advent. Herein, three triazole-conjugated rhodamine dyads with different peripheral substituents were synthesized. The key triazole precursors required for the desired chemistry were prepared by adopting our recently developed CTAB catalyzed mechano-click chemistry. Molecular properties derived from photophysics, electrochemistry and surface morphology of the synthesized dyads were analyzed. Furthermore, frontier molecular orbitals, electronic structure and secondary quantum chemical parameters of dyads were also compared. Screening of dyads for their sensing ability towards an array of alkali, alkaline and transition metal ions exhibited a noticeable naked-eye detection of Cu2+ ions and was confirmed by spectrophotometric titration. The specific binding mode of dyads as probable with Cu2+ over other metal ions attributes to the chemoselectivity.

Strain Tunable Thermoelectric Material: Janus ZrSSe Monolayer

Thermoelectric (TE) performance of the Janus ZrSSe monolayer under biaxial strain is systematically explored by the first-principles approach and Boltzmann transport theory. Our results show that the Janus ZrSSe monolayer has excellent chemical, dynamical, thermal, and mechanical stabilities, which provide a reliable platform for strain tuning. The electronic structure and TE transport parameters of the Janus ZrSSe monolayer can be obviously tuned by biaxial strain. Under 2% tensile strain, the optimal power factor PF of the n-type-doped Janus ZrSSe monolayer reaches 46.36 m W m-1 K-2 at 300 K. This value is higher than that of the most classical TE materials. Under 6% tensile strain, the maximum ZT values for the p-type- and n-type-doped Janus ZrSSe monolayers are 4.41 and 4.88, respectively, which are about 3.83 and 1.49 times the results of no strain, respectively. Such high TE performance can be attributed to high band degeneracy and short phonon relaxation time under strain, causing simultaneous increase of the Seebeck coefficient and suppression of the phonon thermal transport. Present work demonstrates that the Janus ZrSSe monolayer is a promising candidate as a strain-tunable TE material and stimulates further experimental synthesis.