Spectroscopic, quantum computational and molecular docking studies on 1-phenylcyclopentane carboxylic acid.

The vibrational wavenumbers of optimized molecular structure of 1-phenylcyclopentane carboxylic acid (1PCPCA) molecule have been calculated by quantum chemical theory and compared with experimental results. The density functional theory (DFT) approach is followed using the method B3LYP and 6-311++G(d,p) basis set. Using potential energy distribution, all the assignments of the basic vibrational modes were calculated. Natural bond orbital (NBO) and atoms in molecules (AIM) topological studies applied to get the intermolecular interactions of the compound. 1H and 13C chemical shift of NMR was estimated on the molecule and also compared with the experimental spectra. In order to find the band gap, the time-dependent (TD-DFT) method is used to get the higher order energy levels properties and also compared with experimental data of UV-vis spectrum. From the analysis of various spectroscopic studies, there is a good relationship between the experimental and theoretical values obtained. Quantum characters, bio-active nature and reactive areas of the molecule are revealed by Fukui function, molecular electrostatic potential (MEP) and Hirshfeld surface studies. The human enzyme steroidogenic types and their protein targets were tested with this molecule by molecular docking.

Normal co-ordinate analysis, molecular structural, non-linear optical, second order perturbation studies of Tizanidine by density functional theory.

The spectroscopic techniques and semi-empirical molecular calculations have been utilized to analyze the drug Tizanidine (5CDIBTA). The solid phase Fourier Transform Infrared (FTIR) and Fourier Transform Raman (FTR) spectral analysis of 5CDIBTA is carried out along with density functional theory (DFT) calculations (B3LYP) with the 6-311++G(d,p) basis set. Detailed interpretation of the vibrational spectra of the compound has been made on the basis of the calculated potential energy distribution (PED). The individual atomic charges by NPA using B3LYP method is studied. A study on the Mulliken atomic charges, frontier molecular orbitals (HOMO-LUMO), molecular electrostatic potential (MEP) and thermodynamic properties were performed. The electric dipole moment (µ) and the first hyperpolarizability (α) values of the investigated molecule were also computed.

Molecular orbital studies (hardness, chemical potential and electrophilicity), vibrational investigation and theoretical NBO analysis of 4-4'-(1H-1,2,4-triazol-1-yl methylene) dibenzonitrile based on abinitio and DFT methods.

The Fourier transform infrared (FTIR) and FT Raman (FTR) of 4-4'-(1H-1, 2, 4-triazol-1-yl methylene) dibenzonitrile (4-HTMDBN) have been recorded and analyzed. The equilibrium geometry harmonic vibrational frequencies have been investigated with the help of standard HF and DFT methods with 6-31G(d,p) as basis set. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). Theoretical simulations of the FTIR and FTR spectra of the title compound have been calculated. The (1)H and (13)C Nuclear Magnetic Resonance (NMR) chemical shifts of the molecule were calculated by the Gauge including atomic orbital (GIAO) method. The stability of the molecule has been analyzed using natural bond orbital (NBO) analysis. The linear polarizability (α) and the first order hyperpolarizability (ß) values of the investigated molecule have been computed using HF/DFT/6-31G(d,p) methods on the finite field approach. UV-Vis spectrum of the compound is recorded and the electronic properties such as HOMO and LUMO energies, are performed. The directly calculated ionization potential (IP), electron affinity (EA), electronegativity (χ), electrophilicity index (ω), hardness (η) and chemical potential (ρ) are all correlated with the HOMO and LUMO energies with their molecular properties. Mulliken population analysis on atomic charges, molecular electrostatic potential maps (MEP) and thermodynamical properties of title compound at different temperature have been calculated.

Quantum mechanical study of the structure and spectroscopic, first order hyperpolarizability, Fukui function, NBO, normal coordinate analysis of phenyl-N-(4-methyl phenyl) nitrone.

The title compound, Phenyl-N-(4-Methyl Phenyl) Nitrone (PN4MPN) was synthesized and characterized by FT-IR, FT-Raman and (1)HNMR, (13)CNMR spectral analysis. The molecular geometry, harmonic vibrational frequencies and bonding features of the title compound in the ground state are computed at the Hartree-Fock/6-311++G(d,p) and three parameter hybrid functional Lee-Yang-Parr/6-311++G(d,p) levels of theory. The calculated results show that the predicted geometry can well reproduce the structural parameters. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMF). The calculated HOMO and LUMO energies confirm that charge transfer occurs within the molecule. The dipole moment (µ), polarizability (α) and hyperpolarizability (ß) of the investigated molecule is calculated by using HF/6-311++G(d,p) and B3LYP/6-311++G(d,p) methods on the finite field approach. Besides, Molecular Electrostatic Potential (MEP), Natural Bond Orbital analysis (NBO) and thermodynamical properties are described from the computational process. The electron density-based local reactivity descriptor such as Fukui functions are calculated to explain the chemical selectivity or reactivity site in PN4MPN. Finally, the calculations are applied to simulated FT-IR and FT-Raman spectra of the title compound which show good agreement with observed spectra.

Synthesis, spectroscopic (FT-IR, FT-Raman, 13C, 1H, UV) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2(2-Hydroxyphenyl)-N-(4-Methylphenyl) Nitrone.

The title compound, 2(2-Hydroxyphenyl)-N-(4-Methylphenyl) Nitrone (2HPN4MPN) was synthesized and characterized by FT-IR, FT-Raman, UV-Vis and (1)HNMR, (13)CNMR spectral analysis. The molecular geometry, harmonic vibrational frequencies and bonding features of the title compound in the ground state are computed at three parameter hybrid functional Lee-Yang-Parr/6-311++G(d,p) levels of theory. The most stable conformer of 2HPN4MPN is identified from the computational results. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMF). The UV-Vis spectrum was recorded in chloroform solution. The energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) complements the experimental findings. The calculated HOMO and LUMO energies confirm that charge transfer occurs within the molecule. In addition, DFT calculations of the compound, Molecular Electrostatic Potential (MEP), Natural Bond Orbital analysis (NBO) and non-linear optical (NLO) properties are performed at B3LYP/6-311++G(d,p) level of theory. Finally, the calculations are applied to simulated FT-IR and FT-Raman spectra of the title compound which show good agreement with observed spectra.