Mulliken Atomic Charges Research Articles

Antimicrobial activity, toxicity prediction, computational investigation, and molecular docking studies of 2-thiophenecarbonitrile

DFT and Molecular docking are pivotal computational techniques in modern chemistry and drug design. This work investigates the electronic structure and reactivity of 2-thiophenecarbonitrile (2TCN) with an emphasis on important factors such HOMO-LUMO energy gap, MEP, Mulliken atomic charges, natural population analysis, and Mutiwfn ELF, LTD, ALIE, and RDG analysis performed using DFT. The MEP and FMO studies were calculated in various solvents like acetonitrile, water, gas, and methanol. The anti-inflammatory and antioxidant investigations revealed substantial activities by 2TCN. Additionally, molecular docking studies are performed to elucidate the binding interaction between the compound and target proteins, providing insights into its potential therapeutic mechanisms. The results demonstrate the binding energies, interaction residues, and the most favorable docking poses. This approach underscores the integration of theoretical and computational methods in advancing molecule design and therapeutic discovery.

Computational Investigation and Antimicrobial Activity Prediction of Potential Antiviral Drug

The ethyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate (S1) was chosen for this investigation due to its important biological and pharmacological activities. Detailed infrared and Raman spectra have been investigated in both theoretical and experimental. Frontier molecular orbitals and the electronic properties of the S1 are explained. The titled compound S1 calculated HOMO-LUMO energy gap is 4.60 eV. In molecular electrostatic potential (MEP) map the NO2 group exhibits a blue color, indicating the presence of nucleophilic sites. The density of state (DOS), non-covalent interaction (NCI), electron localized function (ELF), localized orbital locator (LOL), Mulliken atomic charges, and reactive sites have been investigated. The anti-bacterial, antifungal, antitoxin, antiviral, and antimycobacterial studies have been investigated. The molecular docking investigations of the compound were also conducted. Using the Auto-dock program, the compound S1 molecular docking study has been conducted. The molecular docking study's lowest binding energy is -7.91, -5.62, -6.92, and -5.85 kcal/mol for 4XGK, 4ATO, 3U9G, and 2DP4 respectively.

Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules.

Multicentre redox metalloproteins undergo conformational changes on electrochemical surfaces, or on enzyme substrate binding. The two-centre copper enzymes, laccase (Type I and TypeII/III Cu) and nitrite reductase (CuNIR) (Type I and Type II Cu) are examples. With some exceptions, these enzymes show no non-turnover voltammetry on Au(111)-surfaces modified by thiol based self-assembled molecular monolayers, but dioxygen or nitrite substrate triggers strong electrocatalytic signals. Scanning tunnelling microscopy also shows high conductivity only when dioxygen or nitrite is present. Atomic force microscopy shows constant CuNIR height but pronounced structural expansion in the electrocatalytic range on nitrite binding. We have recently offered a rationale, based on ab initio quantum chemical studies of water/nitrite substitution in a 740-atom CuNIR fragment. Presently we provide much more detailed structural assignment mapped to single-residue resolution. NO2 --binding induces both a 2 Å Cu-Cu distance increase, and pronounced frontier orbital delocalization strongly facilitating ET between the Cu regions. The conformational changes transmit from the catalytic Type II centre to the electron inlet Type I centre, via the His129-Cys130 ligands, and via Type I-Cys130 or Type I-His129 ending at Type II Asp92. The ET patterns are reflected in different atomic Mulliken charges in the water and nitrite CuNIR fragment.

Vibrational Spectra and Computational Study of Amyl Acetate: MEP, AIM, RDG, NCI, ELF and LOL Analysis

This work is focused on biologically active neat amyl acetate and its solutions in ethanol/heptane. According to the experimental results, when the concentration of amyl acetate in the amyl acetate-ethanol solution decreases, the additional band appears on the low-frequency side. The primary reason for the formation of such additional band is the intermolecular hydrogen bonding between amyl acetate and ethanol. In the amyl acetate-heptane solution, as the concentration of amyl acetate in the solution decreases, the band corresponding to the C=O stretching vibrations shifted to a higher frequency. This is explained by the fact that heptane breaks intermolecular interactions in solution, resulting in a simpler spectral band corresponding to the C=O stretching vibrations. Calculations are also used to study interactions in amyl acetateethanol complexes and their spectral manifestations. When the complex formation energies are calculated, this energy increases with the number of molecules, but the average hydrogen bond energy per one bond remains unchanged. The density functional theory (DFT) method is used to analyze molecular structural parameters: Mulliken atomic charge distribution; thermodynamic parameters; molecular electrostatic potential (MEP) surface; atoms in molecules (AIM) analysis; quantum chemical parameters such as reduced density gradient (RDG) and noncovalent interaction (NCI) analysis; electron localization functions (ELF) analysis; and localized orbital locator (LOL) analysis.

Mechanisms for forming methylglyoxal complexes with benzene and ethanol molecules. Nonempirical calculations

The formation mechanism of methylglyoxal monomers, dimers, trimers, methylglyoxal+benzene, and methylglyoxal+ethanol complexes was investigated using the density functional theory (DFT) approach and the B3LYP/6-311++G(d, p) functional set. Methylglyoxal has two C=O stretching vibrations, and in solvents, the intensity of the first C=O vibration band increased sharply, and the intensity of the second C=O vibration band decreased. This is due to the C=O···H hydrogen bond formed between methylglyoxal+benzene/ethanol solvents. Also, the calculations showed that among the molecules of methyglyoxal+benzene/ethanol mainly weak interactions, i.e. Van der Waals interactions, play a dominant role. Calculations are shown the complex formation energy increases as the number of molecules increases, but the average hydrogen bond energy corresponding to each bond remains unchanged. Also, the DFT method was used to study molecular structure, quantum chemical parameters such as Mulliken atomic charge distribution, atoms in molecules (AIM), reduced density gradient (RDG) and noncovalent interaction (NCI), electron localization functions (ELF), and localized orbital locator (LOL).

Exploring the anti-diabetic activity of 2,6-diamino-4-chloropyrimidinium-hydrogen oxalate conjugates: Synthesis, crystal structure, quantum computational, drug-likeness, molecular docking and dynamics simulation

Inhibiting carbohydrate-hydrolyzing enzyme has been considered as an effective approach for controlling starch digestion and postprandial blood glucose level. The aim of this study, the salt molecule was prepared to identify potentially effective compound against diabetic activity and discover the inhibitory mechanism of the targeted enzyme, which is determined by In-silico techniques. And also perform the quantum chemical calculation to provide insights about the internal motions of the molecule at the atomic level. The 2,6-diamino-4-chloropyrimidinium-hydrogen oxalate (C4H6ClN4+. C2HO4-) was newly synthesized molecule, which is detailly discussed in this present work. The title compound has been confirmed by single-crystal X-ray diffraction studies, and this structure was refined by the least-square refinement method. The crystal compound exhibited the P-1 space group (centrosymmetric) and the following unit cell parameters: a = 5.5778(6)Å, b = 9.6687(10)Å, c = 9.9144(10)Å, α = 116.342(1) °, β = 92.610(1) °, γ = 106.370(1) °, Z = 2. The molecular structure is stabilized by the networks of N–H···O, O–H···O, C–H···O, and N–H···N hydrogen bond interactions. The Hirshfeld surface (HS) analysis and fingerprint plots revealed strong intermolecular interaction between the molecules. The structural optimization, frontier molecular orbital (FMO), molecular reactivity, molecular electrostatic potential (MEP), and mulliken atomic charges were generated by the density functional theory (DFT) calculated at B3LYP/6-311G++ (d,p) theory level. Drug-likeness and physicochemical properties were predicted. The molecular docking analysis was showed a binding energy of −8.96 kcal/mol within the active site of alpha-amylase, which is responsible for anti-diabetic activity. The protein-ligand complex stability was verified using molecular dynamics studies with 100 ns.

Vibrational spectroscopic interpretation, solvent effect and molecular docking studies of TAAR1 partial agonist RO5263397

Density functional theory studies of TAAR1 (trace amine associated receptor 1) partial agonist RO5263397 carried out with precise and detailed spectroscopic investigation as well as validated experimentally. FT-IR, confocal Raman and UV–visible spectroscopic techniques were used to characterize the compound and corresponding theoretical calculations were carried out using DFT/B3LYP method with 6-311++G (d,p) basis set. Estimated and observed vibrational wavenumbers of the compound were assigned. UV–visible spectrum and FMOs (frontier molecular orbital) analysis reveals that the polarity affects the molecular reactivity and stability of the compound. Donor – acceptor interaction and second order perturbation energy have been explained using natural bond orbital analysis clarify the presence hydrogen bonds in the system. ELF and LOL studies visualises the localized and delocalized electrons in the title compound. RDG analysis evidences the various interactions present in the monomer and dimer of RO5263397. The structural importance of the compound were clearly examined using NMR spectral analysis. The existence of hydrogen bonding is validated by reactive site findings from Mulliken atomic charge distribution and molecule electrostatic potential surface studies. Information about distinct drug-receptor interactions obtained from molecular docking investigation offers the path of further study of molecular activity in various drug-receptor mechanism.

Design and synthesis of novel quinoxaline-piperazine linked isoxazole conjugates: Anti-cancer assessment, tyrosine kinase EGFR inhibitory activity, molecular docking and DFT studies

In this paper, we describe the synthesis of a novel series of quinoxaline-piperazine-isoxazole conjugates. We confirmed the structures of the newly synthesised compounds using 1HNMR, Mass, and 13CNMR spectroscopic techniques. The anti-tumour activity was evaluated on two human cancer cell lines, such as MCF-7 (breast) and A-549 (lung). The anti-cancer evaluation dates show that compounds 7f, 7e, and 7 g have more promising anti-cancer activity than the standard drug Erlotinib. We tested three potent compounds (7f, 7e, and 7 g) against a normal breast cell line in a cell survivability test (MCF-10A). Interestingly, none of them killed the cancer cells significantly (IC50 values greater than 88.91 µM). In addition, in vitro tyrosine kinase EGFR inhibitory activity has shown that compounds 7e and 7f display the highest tyrosine kinase EGFR inhibitory potency with an IC50 value of 1.10 and 0.85 µM, respectively, compared to the reference Erlotinib with an IC50 value of 1.24 µM. Furthermore, molecular docking analyses revealed that compounds (7f, 7e, and 7 g) exhibited a higher number of EGFR binding interactions. In this work 7f, the molecule was characterised by using density functional theory (DFT) with B3LYP/6–311G++ (d, p) basis set. The structural parameters were obtained from geometry optimization. Molecular electrostatic potential (MEP), HOMO-LUMO energy gap, and Mulliken atomic charges were calculated. The potent compounds 7f, 7e, and 7 g were subjected to in silico pharmacokinetic assessment by SWISS, ADME, and pkCSM. The three compounds (7e, 7f, and 7 g) intriguingly matched all four of the above-mentioned conditions exactly, with the exception of compound 7f's Ghose rule.

Novel coumarin-Schiff base derived electronically distinct fluorescent probes: Synthesis and comparative investigations of their unique selective sensing properties with Cu2+ and Cu+ ions

The present work describes the synthesis and comparative investigations of Cu2+ and Cu+ ions sensing properties of two novel π-extended coumarin-Schiff base-derived electronically distinct fluorescent probes (4 and 5). Due to the additional electron donating group substituent (-NEt2) close proximate to the binding site of Schiff base in probe 5, it exhibits distinct electronic properties compared to probe 4. Our studies indicate that probe 5 displays efficient and highly selective fluorescence quenching behaviors with Cu2+ and Cu+ ions compared to other competitive metal ions (Ca2+, Mg2+, Al3+, Hg2+, Pb2+, Cd2+, Mn2+, Co2+, Ni2+, Fe2+, Fe3+, Cr3+ and Zn2+). In our studies, Job's plot experiments revealed that the binding stoichiometry of the ligand-Cu2+ was 1:1 for both probes. The limit of detection (LOD) of 2.35 × 10–5 M and 1.56 × 10–5 M were obtained for the probes 4 and 5, respectively. Further, the Stren-Volmer equation has been used to calculate the binding abilities of probes with Cu2+ ions; it reveals the binding constant of 6.70 × 104 M-1 and 22.0 × 104 M-1 for probes 4 and 5, respectively. Also, in the present studies, our DFT computed results were comparatively presented to understand the electronic parameters (HOMO-LUMO energy band gaps, ESP and Mulliken atomic charge distribution) of compound 1, probes 4 and 5. We anticipate that the developed probes can be used to analyze Cu2+ and Cu+ ions in environmental and biological samples.

RGO/CuO NC catalyzed green synthesis, DFT studies, Mulliken atomic charge analysis and anti-inflammatory activity of indole derivatives

An admirable catalytic activity of as-prepared copper oxide decorated reduced graphene oxide nanocomposite (rGO/CuO NC) catalyst is reported in the synthesis of spiro[indoline-pyranothiazole]carbonitrile and thiazolopyranofuroindole derivatives. The excellent activity exhibited by hybrid nanocomposite is attributed to the synergistic effect of graphene oxide and copper oxide nanoparticles. The utilization of ultrasonication as energy source lead to enhanced mass transfer, and reaction rate expeditiousness in the presence of rGO/CuO NC forming spiro/condensed indole derivatives. 100% conversion is observed on Thin Layer Chromatography (TLC). The recovered rGO/CuO NC can be reused for four uninterrupted cycles without substantial loss in its catalytic activity. DFT (Density functional theory) studies, Mulliken atomic charge analysis and anti-inflammatory activity of the synthesized spiro/condensed indole derivatives have also been evaluated.

Aldose Reductase Evaluation against Diabetic Complications Using ADME and Molecular Docking Studies and DFT Calculations of Spiroindoline Derivative Molecule

In this study, the target molecule ethyl-2-(5-nitro-5'-(4-nitrophenyl)-2-oxo-3'H-spiro[indoline-3,2'-[1,3,4]oxadiazol]-1-yl)acetate, which is a spiroindoline derivative, were performed NBO analysis, molecular electrostatic potential surface (MEPS), nonlinear optics (NLO), HOMO-LUMO energy calculations, optimized molecular geometry, and mulliken atomic charges using B3LYP/B3PW91 basis set and 6-311G(d,p) approximations. Calculated results were reported. Density Functional Theory (DFT) computations were utilized to research the molecule theoretically. Moreover, molecular docking analysis of the tested compound, a spiroindoline derivative molecule targeting aldose reductase against diabetic complications, was performed using molecular docking to determine the structure-activity connection. The molecular docking study provided important information worth considering for further research. A notable outcome of bioisosteric and isosteric substitutions is the alteration in lipophilic character, an impressive characteristic in several aspects. Thus, utilizing SwissADME, lipophilic character assessments were performed for the concerned compounds.

Biological evaluation of a novel Schiff base ligand as an antioxidant agent: Synthesis, characterization and DFT computations of its Ni(II) and Cu(II) complexes

By condensation reaction in methanolic medium, a novel ligand using methoxy substituted amine and 5-bromosalicylaldehydic was synthesized. Then, its Cu- and Ni- complexes were also prepared under same experimental conditions. The final desired compounds, with high obtained yields, have been characterized and well discussed by EA-CHN, UV–Vis., FT-IR, NMR, SEM-EDX and MS spectrometry. The structure of the ligand was confirmed by X-ray crystallography showing an interesting intramolecular hydrogen bond and also intermolecular interactions (Br…CArom. and CH/π-type). The electronic properties were quantified by density functional theory (DFT) calculations using DFT- B3LYP/6-31 G (d,p) level basis set. The molecular structures, geometrical parameters, chemical reactivity, stability, molecular electrostatic potential (MEP) and Mulliken atomic charges were computed to identify the chemical reactive sites on the molecular surface. The antioxidant activities were studied theoretically involving various parameters such as bond dissociation enthalpy (BDE), ionization potentials (IPs), proton affinities (PA), proton dissociation enthalpy (PDE), electron transfer enthalpy (ETE) and radical stabilization energy (RSE). Experimentally, the antioxidant activities were also studied by using 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric ion reducing antioxidant power (FRAP) and nitric oxide scavenging (SNP) methods. The computational study of antioxidant activity is well correlated with their experimental results.

Hydration effects on molecular structure, vibrational, electronic properties, drug-likeness analysis, molecular docking, and molecular dynamics studies of (Z)-3-(2-oxo-2-phenylethylidene)indolin-2-one

This study examines how solvation models, including COSMO, CPCM, PCM, and SMD, affect the conformations, molecular structure, vibrational behaviors, and electronic properties of the (Z)-3-(2-oxo-2-phenylethylidene)indolin-2-one (Z3-2O2PEI) molecule within the framework of the B3LYP/cc-pVTZ model chemistry, along with its potential effectiveness as a drug for treating COVID-19. The most stable molecular conformation of the studied coùpound was identified in the presence of the COSMO solvent. The theoretical vibrational frequencies matched the experimentally observed FT-IR and Raman data. Solvent influences on the UV–vis spectra of Z3-2O2PEI revealed electronic transitions from n to π* and π to π* orbitals, along with evidence of intermolecular charge transfer (ICT) supported by analyses of Frontier Molecular Orbitals (FMO) and Natural Bond Orbitals (NBO). The examinations of Mulliken atomic charge distributions and molecular electrostatic potential surfaces reveal the electrophilic and nucleophilic sites of the molecule under study. Non-covalent Interaction (NCI) analysis confirmed the presence of steric effects and Van der Waals interactions within the compound. According to molecular docking studies, the Z3-2O2PEI molecule exhibits significant binding affinity for PLpro, a protein targeted in COVID-19 treatment. This finding is supported by subsequent molecular dynamics analysis, validating the docking results.

3-Pyrazolyl-pyran-2-one: Synthesis, crystal structure, Hirshfeld surface analysis, DFT and ADME studies

Synthesis, crystal structure, Hirshfeld surface analysis, DFT and in-silico studies were carried out for the 4‑hydroxy-6-methyl-3-(1-phenyl-1H-pyrazol-3-yl)-2H-pyran-2-one 2. The reaction efficiency was evaluated performing two conditions to prepare the Vilsmeir-Haack reagent: phosphoryl trichloride in DMF and phosphorus pentachloride in DMF. The molecular structure was confirmed by 1H and 13C NMR, IR spectroscopy and X-ray diffraction analysis. The pyrazole and pyran rings are nearly coplanar. The molecules are connected through C—H···O hydrogen bonds, C—H⋯π and π⋯π stacking interactions, forming layers in the crystal lattice. Hirshfeld surface analysis for crystal packing indicates that the most important contributions are H⋯H (41.6 %), C⋯H/H⋯C (22.6 %), O…H/H…O (20.9 %) interactions. The frontier molecular orbital, Mulliken and QTAIM atomic charge, Molecular Electrostatic Potential, Natural Bond Orbitals were produced using the optimized structure by B3LYP/6–311G(d,p) level of theory. The calculated LUMOHOMO gap (4.261 eV) indicated that the eventual charge transfer and showed chemical reactivity. Intrinsic reaction coordinate (IRC) calculation confirm that the transition state connects the reactants to the products. The experimental geometry parameters of the title compound are compared with the geometry of the optimized molecule in the gas phase and found in good agreement. The crystal structure was further explored to define the interaction energy between the molecular pairs. The ADME profile that pyrazolyl-pyran-2-one 2 is an inhibitor of CYP1A2 one of the five key cytochrome isoforms enzymes involved in drug metabolism.

Synthesis, spectroscopic characterization, biological evaluation studies on 6-methoxy-8-nitroquinolinium picrate: A potent lung cancer drug

The compound 6-Methoxy-8-Nitroquinolinium Picrate was synthesized and characterized using FT-IR, FT-Raman, and UV–Vis spectroscopic techniques. Vibrational wavenumbers were calculated and compared with experimental values, while UV–Vis analysis revealed electronic transitions within the molecule. Frontier molecular orbitals, molecular electrostatic potential surface, Mulliken atomic charge distribution, and Natural bond orbitals analyses confirmed the molecule's bioactivity and validated the intramolecular charge transfer within the molecule. Antibacterial testing exhibited activity against Klebsiella pneumoniae, while in vitro cytotoxicity experiments demonstrated higher inhibition of A549 cancer cell lines compared to HeLa cell lines. Molecular docking supported the in vitro cytotoxicity findings, suggesting the potential for developing new lung cancer treatments based on this research.

Synthesis, crystal structure, spectroscopic characterization, in vitro, molecular docking and DFT studies of 1- (Tert-Butyl) 2-methyl (2S, 4R)-4-hydroxy pyrrolidine-1,2-dicarboxylate

A chiral pyrrolidine-based compound, namely 1-(Tert-Butyl) 2-Methyl (2S, 4R)-4-Hydroxy Pyrrolidine-1,2-Dicarboxylate (NHP), was synthesized and crystallized by the slow evaporation technique. NMR, FT-IR, ESI-MS, UV–visible spectroscopy, and elemental analysis designate the molecule. The molecule crystallized in the orthorhombic space group P212121, identified by X-ray diffraction (XRD). Quantum chemical calculations were performed using DFT at the B3LYP/6–311++G (d,p) level. The DFT-calculated optimal structural parameters and the XRD-derived parameters showed a good correlation. The frequency of NHP is calculated using the DFT method and compared with observed results. The synthesized compound's molecular reactivity was further investigated using Mulliken atomic charges, HOMO-LUMO, and molecular electrostatic potential (MEP). The molecule was tested for molecular docking with bio-enzymes such as α-amylase (1HNY) and cyclooxygenases (1PGG & 4COX). The compound showed 7 hydrogen bonding interactions with 1HNY and 8 hydrogen bonding interactions with 4COX. The DFT investigations strongly support the molecular docking results. The molecule's in-vitro anti-inflammatory and anti-diabetic activity was compared with conventional medication. The NHP showed superior anti-inflammatory activity with protein denaturation technique than the standard diclofenac sodium. The results showed that the molecule outperformed the conventional medication in tests for inflammation.

Structural, spectroscopic (FTIR, FT-Raman and UV–Vis) investigations, Fukui function analysis and thermodynamic properties of diethyl 3,3′-(ethane-1,2-diylbis(azanediyl))(2Z,2′Z)-bis(but-2-enoate)

Diethyl 3,3′-(ethane-1,2-diylbis(azanediyl))(2Z,2′Z)-bis(but‑2-enoate) (DBE) molecule is characterized by infrared, Raman and UV–visible spectroscopic techniques. The structural parameters obtained using density functional theory (DFT) with B3LYP/6-311++G(d,p) level of theory closely match the experimental data. The molecule's characteristic functional groups were identified through vibrational spectra analysis. The IR and Raman spectra vibrational peaks were assigned based on Potential Energy Distribution (PED) analysis. Excitation wavelengths, oscillator strengths and excitation energies were determined through time dependent density functional theory (TD-DFT) calculations and compared to experimental data. Nonlinear optical (NLO) properties were calculated to predict the electric dipole moment and first-order hyperpolarizability of the molecule. The significant nonlinear optical properties values indicated that these materials possess excellent nonlinear optical properties, making them suitable for applications in telecommunication and signal processing. The Mulliken atomic charge, chemical activity analysis and Fukui functions were utilized to investigate the electron-poor, rich and reactive sites in conjunction with the optimized structures using the DFT method with B3LYP function and 6-311++G(d,p) basis set. Thermodynamic investigations have shown that key molecular parameters such as entropy, heat capacity and enthalpy increase as temperature rises.

Physical analysis of aspirin in different phases and states using density functional theory

This study analyzed the aspirin molecule (C9H8O4) using Density Functional Theory (DFT) on Gaussian 09W software. First, the structure of aspirin was optimized using the DFT method with the B3LYP functional and the 6-311+G (d,p) basis set. A global reactivity study was employed to understand the reactivity of aspirin in gas and solvent water for both anion and neutral states. To understand the involvement of orbitals in chemical stability and electron conductivity, we calculated the HOMO-LUMO. The thermodynamic function of a molecule was understood using thermochemistry. Molecular Electrostatic Potential (MEP) was employed to understand the physiochemical properties of aspirin. We observed the Mulliken atomic charge to calculate the atomic charge of aspirin. Finally, the title molecule's UV–Vis, FTIR, and Raman spectra are analyzed and compared with the experimental data.

A DFT-D investigation of the energetic and structural aspects of dehydrogenation of methanol on a bimetallic surface PtGe(110) exploring the germanium effect on the anti-poisoning of pt(110) catalytic activity

Platinum is the most active pure metal for dehydrogenating methanol to create hydrogen, which is crucial for fuel cells. However, one significant disadvantage that reduces the effectiveness and long-term performance of platinum catalysts is their susceptibility to CO poisoning. In the current study, we examine and elucidate the promotional impact of Ge on Pt catalysts with increased resistance to deactivation by CO poisoning. We do this by combining partial density of states calculations with electronic configuration and Mulliken atomic charges. The self-consistent periodic density functional theory with dispersion correction (DFT-D) was used to investigate the methanol adsorption and dehydrogenation mechanisms on the surface of PtGe (110). On the surface, several adsorption mechanisms of pertinent intermediates were found. Furthermore, a thorough analysis of a reaction network comprising four reaction paths revealed that, in terms of activation barriers, the first O—H bond scission of CH3OH appears to be more advantageous than C—H bond cleavage on the PtGe(110) surface. Additionally, it has been demonstrated that the main route on the PtGe(110) surface is CH3OH→CH3O→CH2O→CHO→CO evolution. The remarkable differences in the predominant reaction pathway on the Pt(110) surface, and PtGe(110) surface indicate that the Ge-doped Pt Nano catalyst is more selective and resistant to deactivation.

Studies on the synthesis, growth, and characterization of 2-cyanopyridinium salicylate single crystals for nonlinear optical applications

By employing methanol as the solvent in slow solvent evaporation method, a new nonlinear optical organic single crystal of 2-cyanopyridinium salicylate (2-CPSC) was grown. The lattice parameters of the 2-CPSC crystals were found out to be a = 7.7764(9) Å, b = 12.3938(17) Å, c = 12.3685(18) Å, and β = 94.44º using single crystal X-ray diffraction (SCXRD) analysis. The confirmation of crystalline nature was done by powder XRD analysis. The 2-CPSC crystal's chemical composition and functional groups were confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical study was done by ultraviolet-visible-near infrared (UV–Vis-NIR) spectral analysis showing a cutoff wavelength of 338 nm. Studies on the grown 2-CPSC crystal's dielectric and Vicker's microhardness were also conducted. The linear dependence of photocurrent with the applied electric field was revealed for the grown crystals. The 2-CPSC crystal's third-order nonlinearity was investigated by the single-beam Z-scan technique using a continuous He-Ne laser. The open aperture Z-scan reveals the two-photo absorption mechanism and the closed aperture Z-scan study reveals the positive nonlinearity of the 2-CPSC crystals with third order susceptibility value of χ3=2.6763×10−6(esu). The density functional theory (DFT) method of B3LYP level with the 6–31++G(d,p) basis set was used for different quantum chemical calculations like geometry optimization, natural bond orbital (NBO) analysis, mulliken atomic charge, and molecular electrostatic potential (MEP). The higher nonlinearity of the 2-CPSC can be a potential alternative for commercially available potassium dihydrogen phosphate (KDP) and candidate for its application in nonlinear optical devices like optical limiting and optical switching.