Electronic absorption, vibrational spectra, nonlinear optical properties, NBO analysis and thermodynamic properties of N-(4-nitro-2-phenoxyphenyl) methanesulfonamide molecule by ab initio HF and density functional methods

pH-Responsive Graphene Oxide-Based 2D/3D Composite for Enhancing Anti-Corrosion Properties of Epoxy Coating

The functionalized graphene oxide (GO)-based composites as fillers added into organic coatings are desired for realizing the longstanding corrosion protection of carbon steel. Here, the pH-responsive two-dimensional/three-dimensional (2D/3D) GO-based composite (ZIF-90-AAP/GO) was developed by environmentally friendly corrosion inhibitor 4-aminoantipyrine (AAP) anchored on the in situ growth of zeolite imidazolate framework-90 (ZIF-90) on the GO surface (ZIF-90/GO) through the Schiff base reaction. The active filler (ZIF-90-AAP/GO) was incorporated into an epoxy coating (EP) to obtain a high-performance self-healing coating on the surface of carbon steel. ZIF-90-AAP can greatly improve dispersion and compatibility of GO in EP. The low-frequency impedance modulus of ZIF-90-AAP/GO-EP can still reach up to 1.35 × 1010 Ω⋅cm2 after 40 days, which is about three orders of magnitude higher than that of the EP containing GO (GO-EP) relying on its passive and active corrosion protection. Meanwhile, ZIF-90-AAP/GO-EP exhibits excellent self-healing performance. The self-healing rate of ZIF-90-AAP/GO changes from negative to positive after 24 h, which results from the effective corrosion inhibition activity of ZIF-90-AAP for carbon steel based on the pH-triggered controlled release of AAP. The developed pH-responsive 2D/3D GO-based composite coating is very attractive for the corrosion protection of carbon steel.

Quantum mechanical studies of p-azoxyanisole and identification of its electro-optic activity

Liquid crystals (LCs) are used in displays, visors, navigation systems and many more. Amongst a wide range of LCs, p-azoxyanisole (PAA) is considered to be an active LC. Focusing on different properties of this molecule, in the reported study, the theoretical identification of quantum mechanical parameters and the identification of electro-optic properties are carried out. Different functional theories such as B3LYP, M06-2X and M06L are used along with three basis sets 6-31G**, 6-311G and 6-311G**. A comparative study revealed that the M06-2X method produces higher values of band gap, ionization potential, electronegativity and electronic global hardness while M06L produces lower values and B3LYP gives intermediate values. Nonlinear optical properties of liquid crystals are evaluated. The nonlinear optical properties obtained for a PAA liquid crystal are much higher than those of urea. Due to its high nonlinear optical properties, our liquid crystal can be used in the field of telecommunication and optical interconnection. The order parameter and birefringence are calculated with variable electric field. We found out that the order parameter and birefringence increase with a gradually increasing electric field, which suggests that the PAA liquid crystal can be used for developing electro-optic and tunable metamaterial devices.

Efficient photo-Fenton catalysis using magnetic iron nanoparticles decorated boron nitride quantum dots: theoretical and experimental investigations

To achieve the efficient removal of pharmaceutical wastes, novel photo-Fenton catalysts, iron-decorated boron nitride quantum dots (Fe@BNQDs) were prepared. Fe@BNQDs were characterized using XRD, SEM-EDX, FTIR, and UV-Vis spectrophotometry. The decoration of Fe on the surface of BNQDs enhanced the catalytic efficiency due to the photo-Fenton process. Photo-Fenton catalytic degradation of folic acid was investigated under UV and visible light. The influence of H₂O₂, catalyst dose, and temperature on the degradation yield of folic acid was investigated using Response Surface Methodology. Moreover, the efficiency of the photocatalysts and kinetics was investigated. Radical trapping experiments revealed that holes were the main dominant species in the photo-Fenton degradation mechanism and BNQDs played active roles because of their hole extraction ability. Additionally, active species such as e^- and O₂ ^-˙ have a medium effect. The computational simulation was utilized to provide insights into this fundamental process, and for this purpose, electronic and optical properties were calculated.

Synthesis, single crystal (XRD), Hirshfeld surface analysis, computational study (DFT) and molecular docking studies of (E)-4-((2-hydroxy-3,5-diiodobenzylidene)amino)-N-(pyrimidine)-2-yl) benzenesulfonamide

The Schiff base (E)-4-((2-hydroxy-3,5-diiodobenzylidene)amino)-N-(pyrimidine)-2-yl) benzene sulfonamide (DIDA) compound was synthesis with condensation of 3,5-diiodosalicylaldehyde and sulfadiazine. The compound characterized with FTIR, X-ray crystallography and electronic spectra. The titled compound associated with experimental and theoretical method, DFT used for the theoretical method. The IR was calculated from DFT mode with B3LYP/GENSEP basic set. The electronic spectra computed from TD-DFT method with CAM-B3LYP functional, with IEFPCM solvation model and DMSO used as the solvent. Wave function based properties like localized orbital locator, electron localization function and non-covalent interactions have been studied extensively. The ADMET properties of the compound DIDA indicated that the compound has excellent drug likeness properties and PASS studies showed that it has anti-infective properties, which is confirmed by a docking score of -7.4 kcal/mol.

Quantum chemical insight into molecular structure, NBO analysis of the hydrogen-bonded interactions, spectroscopic (FT-IR, FT-Raman), drug likeness and molecular docking of the novel anti COVID-19 molecule 2-[(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(4-fluorophenyl)acetamide - dimer

Novel antiviral active molecule 2- [(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(4-fluoro- phenyl)acetamide has been synthesised and characterized by FT-IR and FT-Raman spectra. The equilibrium geometry, natural bond orbital calculations and vibrational assignments have been carried out using density functional B3LYP method with the 6-311G++(d,p) basis set. The complete vibrational assignments for all the vibrational modes have been supported by normal coordinate analysis, force constants and potential energy distributions. A detailed analysis of the intermolecular interactions has been performed based on the Hirshfeld surfaces. Drug likeness has been carried out based on Lipinski's rule and the absorption, distribution, metabolism, excretion and toxicity of the title molecule has been calculated. Antiviral potency of 2- [(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(4-fluoro-phenyl) acetamide has been investigated by docking against SARS-CoV-2 protein. The optimized geometry shows near-planarity between the phenyl ring and the pyrimidine ring. Differences in the geometries due to the substitution of the most electronegative fluorine atom and intermolecular contacts due to amino pyrimidine were analyzed. NBO analysis reveals the formation of two strong stable hydrogen bonded N-H···N intermolecular interactions and weak intramolecular interactions C-H···O and N-H···O. The Hirshfeld surfaces and consequently the 2D-fingerprint confirm the nature of intermolecular interactions and their quantitative contributions towards the crystal packing. The red shift in N-H stretching frequency exposed from IR substantiate the formation of N-H···N intermolecular hydrogen bond. Drug likeness and absorption, distribution, metabolism, excretion and toxicity properties analysis gives an idea about the pharmacokinetic properties of the title molecule. The binding energy -8.7 kcal/mol of the nonbonding interaction present a clear view that 2- [(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(4-fluoro- phenyl) acetamide can irreversibly interact with SARS-CoV-2 protease.

Quantum mechanical, spectroscopic and docking studies of (2E)-1-(4-aminophenyl)-3-(4-benzyloxyphenyl)-prop-2-en-1-one Chalcone derivative by density functional theory - A prospective respiratory drug

Theoretical investigations on the molecular geometry, vibrational and electronic environment of (2E)-1-(4-aminophenyl)-3-(4-benzyloxyphenyl)-prop-2-en-1-one (APBPP) are presented for the first time. The vibration frequencies simulated were thoroughly analysed employing DFT/B3LYP using 6-311++G(d,p) basis set and compared with experimental FT- Raman and FT- IR data which showed good agreement vice-versa. Optimised molecular equilibrium geometry of the title compound was carried out. Vibrational assignments of wave numbers with PED (potential energy distribution) was done using VEDA software and the quantum chemical calculations of the molecular geometry were scaled using quantum mechanics. The title molecule showcased excellent results on HOMO - LUMO energies, NMR chemical shifts, 3.73 eV band gap, electronegativity (χ), chemical potential (μ), softness (S), global hardness (η). The low softness value (0.261) and thehigh value of electrophilicity index (4.0323) explains the biological activity of the title molecule. The reactive sites of APBPP were thoroughly investigated by Mulliken charges, MEP (Molecular electrostatic Potential) and Fukui functions. Thermo dynamical environment of the title compound for different temperatures were studied which reveals the correlations between entropy (S), heat capacity (C) and enthalpy changes (H) with temperatures. The title compound was docked into the reactive sites of antiviral (SARS-CoV-1,2) and anticancer protein using molecular docking tool and it showed excellent results compared to the ongoing clinical trials. The paper explains the experimental analysis which are in line with the quantum calculations and presents an optimistic evidence via Molecular docking studies. The synthesized compound against various panels of microorganism projects its ability to be the most potential drug to treat various pathologies in pharmacy Industry.

Investigations on 2-(4-Cyanophenylamino) acetic acid by FT-IR,FT-Raman, NMR and UV-Vis spectroscopy, DFT (NBO, HOMO-LUMO, MEP and Fukui function) and molecular docking studies

Extensive quantum chemical calculation have been carried out to investigate the Fourier Transform Infrared(FT-IR), Fourier Transform Raman(FT-RAMAN) and Nuclear magnetic resonance(NMR), and Ultra Violet-Visible(UV-vis) spectra of 2-(4-Cyanophenylamino) acetic acid. The molecular structure, fundamental vibrational frequencies and intensities of the vibrational bands were interpreted with the aid of optimizations and normal coordinate force field calculations based on density functional theory (DFT) and ab initio HF methods with 6–311++G(d,p) basis set. The theoretical vibrational wavenumbers are compared with the experimental values. The calculated HOMO-LUMO energies were found to be-6.2056 eV and -1.2901 eV which indicates the charge transfer within the molecule. Natural bond orbital analysis has been carried out to explain the charge transfer (or) delocalization of charge due to the intra molecular interactions. Molecular Electrostatic Potential (MEP), First order hyperpolarizability, and Fukui functions calculation were also performed. The thermodynamic properties of the title compound were studied for different temperatures. Molecular docking studies were made on the title compound to study the hydrogen bond interactions and the minimum binding energy was calculated.

PES, molecular structure, spectroscopic (FT-IR, FT-Raman), electronic (UV-Vis, HOMO-LUMO), quantum chemical and biological (docking) studies on a potent membrane permeable inhibitor: dibenzoxepine derivative

The dibenzoxepines derivatives have found a broad application in biological and pharmaceutical fields as new prospective drugs. So, the molecule (3aS,12bS)-5-Chlor-2-methyl-2,3,3a,12b-tetrahydro-1H-dibenzo[2,3:6,7]oxepino[4,5-c]pyrrol has been characterized by DFT (Density Functional Theory) approach to predict the important properties of it. The minimum energy conformer has been found by PES (Potential Energy Surface) and then the structure is optimized. Further, the structure is characterized spectroscopically by FT-IR and FT-Raman techniques to know the functional group and chemically active atoms. The geometrical parameters, PED (Potential Energy Distribution) assignments have also been reported. The electronic properties of the title compound have been explained by UV-Vis and HOMO-LUMO analyses that describe the charge transfer between the atoms of the molecule. Molecular Electrostatic Potential (MEP), Electron Localization Function (ELF) and Localized Orbital Locator (LOL) have been depicted to know the chemically active regions. The electrophilic and nucleophilic regions have been shown by Fukui functions. The Non-Linear Optics (NLO) for non-linear optical effects and the Natural Bond Orbital (NBO) for charge delocalization were studied. To study the biological activity of the title compound, molecular docking has been performed which suggests that the title molecule may act as a membrane permeable inhibitor.

Spectroscopic (FT-IR, FT-Raman, UV and NMR) investigation on 1-phenyl-2-nitropropene by quantum computational calculations

In this paper, the spectral analysis of 1-phenyl-2-nitropropene is carried out using the FTIR, FT Raman, FT NMR and UV-Vis spectra of the compound with the help of quantum mechanical computations using ab-initio and density functional theories. The FT-IR (4000-400 cm(-1)) and FT-Raman (4000-100 cm(-1)) spectra were recorded in solid phase, the (1)H and (13)C NMR spectra were recorded in CDCl3 solution phase and the UV-Vis (200-800 nm) spectrum was recorded in ethanol solution phase. The different conformers of the compound and their minimum energies are studied using B3LYP functional with 6-311+G(d,p) basis set and two stable conformers with lowest energy were identified and the same was used for further computations. The computed wavenumbers from different methods are scaled so as to agree with the experimental values and the scaling factors are reported. All the modes of vibrations are assigned and the structure the molecule is analyzed in terms of parameters like bond length, bond angle and dihedral angle predicted by both B3LYP and B3PW91 methods with 6-311+G(d,p) and 6-311++G(d,p) basis sets. The values of dipole moment (μ), polarizability (α) and hyperpolarizability (β) of the molecule are reported, using which the non-linear property of the molecule is discussed. The HOMO-LUMO mappings are reported which reveals the different charge transfer possibilities within the molecule. The isotropic chemical shifts predicted for (1)H and (13)C atoms using gauge invariant atomic orbital (GIAO) theory show good agreement with experimental shifts. NBO analysis is carried out to picture the charge transfer between the localized bonds and lone pairs. The local reactivity of the molecule has been studied using the Fukui function. The thermodynamic properties (heat capacity, entropy and enthalpy) at different temperatures are also calculated.

Synthesis, structural, spectral (FTIR, FT-Raman, UV, NMR), NBO and first order hyperpolarizability analysis of N-phenylbenzenesulfonamide by density functional theory

In this study sulfonamide compound, N-phenylbenzenesulfonamide (NPBS) has been synthesized and grown as a high quality single crystal by the slow evaporation solution growth technique. The grown crystals were characterized by the Fourier transform infrared (4000-400cm(-1)), Fourier transform Raman (3500-500cm(-1)), UV-Vis (200-800nm) and NMR spectroscopy. Density functional (DFT) calculations have been carried out for the compound NPBS by utilizing DFT level of theory using B3LYP/6-31G(d,p) as basis set. The theoretical vibrational frequencies and optimized geometric parameters such as bond lengths and bond angles have been calculated by using quantum chemical methods. The stability of the molecule arising from hyper conjugative interaction and charge delocalization has been analyzed using NBO analysis. The dipole moment, linear polarizability and first order hyperpolarizability values were also computed. The chemical reactivity and ionization potential of NPBS were also calculated. In addition, Molecular Electrostatic Potential (MEP), Frontier Molecular Orbital (FMO) analysis was investigated using theoretical calculations. The thermodynamic properties of the compound were calculated at different temperatures and corresponding relations between the properties and temperature were also studied. Finally, geometric parameters, vibrational bands were compared with available experimental data of the molecules.

DFT calculations and experimental FT-IR, dispersive-Raman and EPR spectral studies of Copper (II) chloride complex with 3-amino-1-methylbenzene

In this study, we present the synthesis and the characterization of Copper (II) chloride complex with 3-amino-1-methylbenzene (3A1MB). This complex was characterized by vibrational and EPR spectroscopic techniques and elemental analysis. The molecular structure and spectrometry of this complex: Cu(3A1MB)2Cl2 and its ligand: 3A1MB have been investigated theoretically by performing DFT/B3LYP calculations. Cu(3A1MB)2Cl2 has been optimized as two conformers and the more stable conformer is determined. The optimized geometries and calculated vibrational frequencies have been evaluated via comparison with experimental values, and the normal modes were assigned on the basis of the percent potential energy distribution (PED). A good agreement between calculated and experimental data is observed.

Vibrational and UV spectra, first order hyperpolarizability, NBO and HOMO-LUMO analysis of 4-chloro-N-(2-methyl-2,3-dihydroindol-1-yl)-3-sulfamoyl-benzamide

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 4000-100 cm(-1) and 4000-400 cm(-1), respectively, for 4-chloro-N-(2-methyl-2,3-dihydroindol-1-yl)-3-sulfamoyl-benzamide (C16H16O3N3SCl) molecule. Theoretical calculations were performed by density functional theory (DFT) method using 6-31G(d,p) and 6-311G(d,p) basis sets. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The frontier orbital energy gap and dipole moment illustrates the high reactivity of the title molecule. The first order hyperpolarizability (β0) and related properties (μ, α, and Δα) of the molecule were also calculated. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The UV-vis spectrum of the compound was recorded in the region 200-400 nm in ethanol and electronic properties such as excitation energies, oscillator strength and wavelength were calculated by TD-DFT/B3LYP method. Molecular electrostatic potential (MEP) and HOMO-LUMO energy levels are also constructed. The thermodynamic properties of the title compound were calculated at different temperatures.

Crystal structure, spectroscopic characterization and density functional studies of (E)-1-((3-methoxyphenylimino)methyl)naphthalen-2-ol

The Schiff base compound (E)-1-((3-methoxyphenylimino)methyl)naphthalen-2-ol was synthesized from the reaction of 2-hydroxy-1-naphthaldehyde with 3-methoxyaniline. The structural properties of the compound has been characterized by using FT-IR, UV-vis and X-ray single-crystal methods. According to X-ray diffraction result, the title compound exists in the phenol-imine tautomeric form. The molecular geometry, vibrational frequencies of the compound in the ground state have been calculated using the density functional theory (DFT/B3LYP) method with the 6-311++G(d,p) basis set, and compared with the experimental data. The obtained results show that the optimized molecular geometry is well reproduce the crystal structure. The theoretical vibrational frequencies are in good agreement with the experimental values. The calculations of electronic absorption spectra of tautomeric forms of the compound were performed by using TD-DFT calculations both in the gas phase and ethanol solvent. To investigate the tautomeric stability, optimization calculations at the B3LYP/6-311++G(d,p) level were performed for the phenol-imine and keto-amine forms of the compound. According to calculated results, the OH form is more stable than NH form. In addition, molecular electrostatic potential (MEP), frontier molecular orbital analysis (HOMO-LUMO), thermodynamic and, non-linear optical (NLO) properties of the compound were investigated using same theoretical calculations.

Identification of structural and spectral features of synthesized cyano-stilbene dye derivatives: a comparative experimental and DFT study

The synthesized three dye derivatives of cyano-stilbene monomer were identified by experimental spectroscopic techniques and density functional approach. The optimized geometrical structure, vibrational and electronic transitions along with the nonlinear optical (NLO) properties of those compounds were presented in this study. The vibrational spectra of investigated compounds were recorded in solid state with FT-IR and FT-Raman spectrometry in the range of 4000-400 cm(-1) and 3600-50 cm(-1), respectively. The theoretical ground state equilibrium conformations and vibrational wavenumbers were carried out by using density functional method with 6-311G(d,p) basis set. Assignments of the fundamental vibrational modes were examined on the basis of the measured data and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The UV absorption spectra of monomers were observed in the range of 200-600 nm in chloroform, acetonitrile and toluene, and time dependent DFT method was used to obtain the electronic properties. The linear polarizability and first hyperpolarizability of the studied molecules indicates that the title compounds can be used as a good nonlinear optical material. A detailed description of spectroscopic behaviors of compounds was given based on the comparison of experimental measurements and theoretical computations.