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The compound (E)-1-(4-bromobenzylidene)semicarbazide(4BSC) was synthesized and characterized by FT-IR, FT-Raman, UV–Visible, 1 HNMR and 13 CNMR spectra. The optimized molecular geometry(bond length, bond angle), the complete vibrational frequency, the infrared intensities and the Raman scattering activities were calculated by using density functional theory(DFT) B3LYP method with the help of 6–311++G(d,p) basis set. From the recorded UV–Visible spectrum, the electronic properties such as excitation energies, wavelength, band gap and oscillator strength are evaluated by TD-DFT in DMSO solution and gas phase methods using 6-311++G(d,p) basis set. The calculated HOMO - LUMO band gap energies confirm that charge transfer occurs within the molecule. The 1 H and 13 C nuclear magnetic resonance (NMR) chemical shifts of the molecule are calculated by the gauge-independent atomic orbital (GIAO) method and compared with experimental results. The hyperconjugative interaction energy E(2) and electron densities of donor (i) and acceptor (j) bonds were calculated using NBO analysis. Besides NLO and MEP were also calculated and interpreted. To study the biological activity of the investigation molecule, molecular docking was done to identify the hydrogen bond lengths and binding energy with different antimicrobial protein. Thermodynamic properties of the title compound at different temperatures have been calculated, revealing the correlations the heat capacity (C), entropy (S) and enthalpy changes (H) and temperatures. [ABSTRACT FROM AUTHOR]

The title compound (RS) - 2- (1, 8-Diethyl- 4, 9-dihydro-3H- pyrano [3, 4-b] indol-1-yl) acetic acid (Etodolac) was characterized by experimental FTIR, FT-Raman, NMR and UV-Visible spectral analysis. The optimized molecular geometry and vibrational wave numbers were calculated by employing the method of DFT and B3LYP/6-311++G(d, p) basis set. The vibrational assignments were calculated using VEDA program. Carbon and Proton NMR chemical shifts were calculated in different solvents by GIAO method. Theoretical UV-Visible spectrum was obtained in DMSO and in gas phase using TD-DFT method. For the title compound, HOMO-LUMO and Donor- Acceptor (NBO) interactions were studied. In addition, MEP map was traced to find the reactive sites of Etodolac. Further, NLO properties such as dipole moment, linear and first order hyperpolarizabilities have been studied to reveal NLO nature of the title compound. Also the thermodynamic properties with respect to temperature were calculated. All the theoretical predictions were carried out by using DFT-B3LYP method at the level of 6–311++G(d, p). Finally to find its biological importance, the molecular docking interaction was studied to reveal that Etodolac is a selective inhibitor of COX (cyclooxygenase) enzyme. Image 1 • A detailed spectroscopic study (FTIR, FT-Raman, NMR and UV-Visible) on Etodolac was reported. • Optimized geometrical parameters were calculated by DFT-B3LYP/6-311++G(d,p). • Vibrational assignments on PED basis was carried out using VEDA program. • NBO, HOMO-LUMO, MEP, NLO and Thermodynamic properties were studied. • Molecular docking simulations have been performed using Auto Dock 4.2.6. [ABSTRACT FROM AUTHOR]

Abstract The molecule (RS)-2-(tert-Butylamino)-1-(3-chlorophenyl)propan-1-one (2B3CP) was optimized utilizing density functional theory (DFT) with B3LYP/6–311++G (d,p) basis set. The vibrational frequencies and potential energy distribution (PED) of 2B3CP molecules were calculated and compared with experimental calculations. The reactivity nature of the molecule was analyzed with various DFT methods such as local reactivity descriptors, Molecular electrostatic potential (MEP), Frontier Molecular orbitals (FMOs), Natural bond orbitals (NBO), etc. The molecular docking analysis reveals that inhibitory nature of the 2B3CP molecule with Adrenaline uptake inhibitor (PDB ID: 2AN5) protein act as neurotransmitter for Central nervous system (CNS) drug discovery. Hence, the present studies report the structural and bioactive nature of the title molecule. Graphical abstract Image Highlights • Molecular docking studies suggest that the compound exhibit adrenaline uptake inhibitor. • Spectroscopic analysis was done by experimental and DFT methods. • The complete assignments of FT-IR and FT-Raman modes were proposed based on the calculated PED % values. • NBO analysis was carried out and thermodynamic properties were predicted. • Hyperpolarizability, HOMO, LUMO energies and Fukui functions were calculated. [ABSTRACT FROM AUTHOR]

FT-IR and FT-Raman spectra of 5,5-diphenylimidazolidine-2,4-dione (55D24D) were recorded and theoretical study has been done by quantum mechanical calculations of DFT using Gaussian software package. The structural, vibrational and electronic properties of the title compound were presented using the B3LYP method with 6–311++G(d,p) basis set. The experimental vibrational spectra were compared with the calculated spectra and each wavenumber was assigned on the basis of potential energy distribution (PED). Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed utilizing Natural bond orbital (NBO) analysis. The electron density-based local reactivity descriptors such as Fukui functions are calculated to explain the chemical selectivity or reactivity site in the title compound. The linear polarizability ( α ) and the first order hyperpolarizability (β) values of the investigated molecule have been calculated. The HOMO and LUMO energies show the chemical activity of the molecule. Mulliken population analysis on atomic charges, Molecular electrostatic potential maps (MEP) and thermodynamical properties of title compound have been calculated. To study the biological activity of the investigation title molecule, molecular docking was done to identify the hydrogen bond lengths and binding energy. [ABSTRACT FROM AUTHOR]

Ketorolac [(±)-5-Benzoyl-2, 3-dihydro-1H-pyrrolizine-1-carboxylic acid] have been investigated by experimental FTIR, FT-Raman, NMR and UV–Visible spectroscopy. The optimized molecular geometry and vibrational wave numbers were calculated by DFT combined B3LYP/6–311++G (d, p) basis set. The detailed vibrational assignments were carried out using VEDA program. Theoretical UV–Vis absorption spectrum was obtained in water using TD-DFT method. To determine the frontier molecular orbital energy gap and to confirm the electronic transition properties of the title molecule, the donor-acceptor (HOMO-LUMO), and for the intra molecular interactions NBO were studied. In order to get the precise chemical structure (shape and size) and reactivity, topology analyses were carried out. Further, the Non-Linear Optical (NLO) properties such as dipole moment, total linear and first order hyper polarizabilities have been studied to reveal the NLO nature. Also thermodynamic propertiess with respect to temperature were calculated. Considering the biological importance, pharmacological molecular descriptors have been computed. The anti inflammatory activity of the title compound docked into the active sites of the target protein was studied from docking parameters. Image 1 • Structural parameters were obtained by DFT-B3LYP method with higher basis set. • Comprehensive spectral analyses such as FTIR, FT-Raman, NMR and UV–Visible were reported. • Topology analyses on the surface of the title compound were carried out. • Charge transfer within molecule and chemical reactivity were reported. • Biological activity was revealed by molecular docking study. [ABSTRACT FROM AUTHOR]

Abstract A molecule 4-chloro-N-(4,5-dihydro-1H-imidazol-2-yl)-6-methoxy-2-methylpyrimidin-5-amine plays a significant role in the treatment of hypertension and acts as a potential I 1 imidazoline receptor agonist. In this present work, the molecular structure of the title compound has been investigated using experimental (FT-IR, FT-Raman and NMR) and theoretical (DFT) techniques. R2 values of FR-IR, FT-Raman and bond lengths state the coherence between theoretical and experimental values. Asymmetric, symmetric stretching and bending vibrations were reported. The geometrical parameters obtained theoretically are in agreement with experimental values. Chemical activity region of the molecule (MEP), molecular stability, charge localization and delocalization (NBO), occupied and unoccupied molecular orbitals (HOMO-LUMO), dipole moment, polarizability and hyperpolarizability (NLO) have been calculated. There is a significant change in a net atomic charge distribution with a corresponding increase in the value of total dipole moment. Furthermore, the mulliken population analysis on atomic charges (electronic properties), thermodynamic parameters at various temperatures have also been calculated. To study the biological activity, different proteins for ligand have been taken and the results suggest that the compound might exhibit anti-hypertensive activity. Henceforth, Quantum mechanical calculations have been done for the title compound to get optimized structure and electronic energies for biological, physical, pharmaceutical and medicinal interest. Graphical abstract Image 1 Highlights • Spectroscopic interpretation of 4NDIM5 has been carried out. • HOMO–LUMO energies and dipole moment have been obtained. • Local reactivity using Fukui function, NBO and MEP diagram were computed and analyzed. • Molecular docking and Drug-likeness were also discussed. [ABSTRACT FROM AUTHOR]

• Vibrational assignment carried out. • FOM theory, UV-Visible and DOS spectra are investigated. • Hirshfeld surface, NBO, NLMO, NHO and MEP are analyzed. • Drug- likeness, ADMET, and molecular docking investigation. The title compound, (2E)-3-(Biphenyl-4-yl)-1-(2,4-dichlorophenyl)-prop-2-en-1-one (BPDC) has been derived from the compounds namely biphenyl-4-carbaldehyde and 2,4-dichloroacetophenone to perform 3D-Potential energy conformations for molecular stability by DFT calculation of B3LYP/6-311++G(d,p). The geometrical optimization and atoms vibrational spectral data observed FT-IR and FT-Raman spectra values were compared with theoretical values (B3LYP, CAM-B3LYP). The molecule was characterized by absorbed infrared radiation, scattered Raman techniques with the attention on important functional groups (Cl, O, N). Electro negativity difference has been discussed and their biochemical and biomedical properties have been examined. The chemical reactivity of the compound was characterized by MEP-map, NHO, NLMO, and NBO analyses. The frontier molecular orbital (HOMO–LUMO) energy gap, vertical electron truncation of UV–Visible spectrum, and their λ-max value have been compared with CAM-B3LYP and M062X/6-311++G(d,p) approach data. The orbitals arrangements were studied by the density of states (DOS) and the partial density of states (PDOS). BPDC is investigated by Hirshfeld surface analysis that employs three-dimensional contours and two-dimension fingerprint area for intermolecular interactions quantitatively. The biological investigations like drug-likeness and toxicity properties of BPDC molecule were conformed to Lipinski's rule of five and ADMET properties, respectively. The title molecule exhibits a good bioactive score and less toxicity. Antibacterial and also antifungal activities of BPDC were done by docking analysis. Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]

4-Hydroxybenzamide (4HBM) molecule was optimized geometrically and vibrational spectral analyses of monomer and dimer structures have been reported by DFT calculations using B3LYP/6–311++G(d,p) level of theory. The molecular structural parameters of the title compound have been observed experimentally and compared with the theoretical (monomer and dimer) data. The experimental FT-IR and FT-Raman vibrational spectral data have been compared with the computational data. The experimental NMR (1H and 13C) chemical shifts have been compared with the calculated chemical shifts that obtained by GIAO (Gauge–Independent Atomic Orbital) theoretical method. The experimental UV–Visible spectrum and vertical electron transition energies were compared with values that found by TD–DFT approach. The electron charge transition by Frontier molecular orbitals theory (HOMO–LUMO energy gap), important chemical reactivity and electron–hole charge transitions have also been studied. Furthermore, the intermolecular interactions have been interpreted using NHO, NLMO, and NBO analyses. The antibacterial and antifungal activities of 4HBM were studied using molecular docking program and the values are compared with the experimental results. The formative role played by the chemical and biological parameters are calculated using spectroscopic and DFT methods and correlated with antibacterial and fungal inhibitory activities which were done by Quantitative Structure-Activity Relationship(QSAR) study. In this present work, 4-Hydroxybenzamide (4HBM) molecule was optimized geometrically and vibrational spectral analysis for monomer and dimer structures have been reported by DFT calculation using B3LYP/6–311++G(d,p) level of theory. The molecular structural parameters of the title compound have been observed and compared with monomer, dimer respectively. The experimental NMR (1H and 13C) chemical shifts have been compared with the chemical shifts which have been obtained by GIAO theoretical method. The experimental UV–Visible spectrum and vertical electron transition energies were compared with the values which were found by TD–DFT approach. The electron charge transition by Frontier molecular orbitals theory, important chemical reactivity and electron–hole charge transitions have also been studied. Furthermore, the intermolecular interactions have been interpreted using NHO, NLMO, and NBO analyses. The antibacterial and antifungal activities of 4HBM were studied using molecular docking program and their values are compared with the experimental results. The formative role played by the chemical and biological parameters of molecule is calculated using DFT methods and that is correlated with the antibacterial and fungal inhibitory activities which were done by Quantitative Structure-Activity Relationship (QSAR) study. Image 1 • In this work, conformation behaviors of PES and FT-IR, FT-Raman spectral analysis of monomer and dimer structure of 4HBM. • UV-Visible, NMR chemical shift were investigated. • The FMO theory, NBO, NLMO, NHO and Chemical reactivity was investigated. • Protein-ligand interactions were analyzed. • QSAR studies that establish relationship between chemical descriptors and antibacterial and fungus inhibitory activity. [ABSTRACT FROM AUTHOR]

The bromo based theyophen chalcone derivative 1-(3-Bromo-2-thienyl)-3-[4-(dimethylamino)-phenyl] prop-2-en-1-one (BTDAP) has been investigated by spectroscopy and quantum chemistry methods using Gaussian09 software package. The stable conformation of molecular structure, vibrational frequencies and electronic absorption spectra were established using B3LYP/6-311++G(d,p) and M062x/6-311++G(d,p) calculations. The Infrared intensities, Raman scattering active regions have been calculated. UV–Visible absorption spectrum has showed the best agreement with their experimental results. The formation of the donor and the acceptor stabilization energies, molecular bonding which is composed from orbitals that have been localized on different atoms and molecular bond angular properties were investigated using NBO, NLMO and NHO calculations. Frontier molecular orbital analysis which explains the energy gap between the ground state HOMO and first excited state LUMO energies were determined. Besides, the chemical properties of condensed Fukui function, MEP and electron-hole charge transfer within the molecule due to excitation for three excited states were obtained by multiwfn software. Molecular docking studies were performed for the title compound with Monoamine oxidase A and B inhibitions. In this present work, the bromo based theyophen chalcone derivative of 1-(3-Bromo-2-thienyl)-3-[4-(dimethylamino)-phenyl] prop-2-en-1-one (BTDAP), we reported stable conformation of molecular structure, vibrational frequencies and electronic absorption spectra were established using B3LYP/6-311++G(d,p) and M062x/6-311++G(d,p) calculations. The Infrared intensities, Raman scattering active regions have been calculated. UV–Visible absorption spectrum has showed the best agreement with their experimental results. The chemical and electronic properties of NBO, NLMO and NHO calculations, Frontier molecular orbital, condensed Fukui function, MEP and electron-hole charge transfer within the molecule due to excitation for three excited states were obtained by multiwfn software. Molecular docking studies were performed for the title compound with Monoamine oxidase A and B inhibitions. • In this work, conformation behaviors of PES and molecular structure stability were studied. • Vibrational wave numbers are assigned using PED analysis. • The chemical reactivity was analyzed by NBO, HOMO-LUMO and Condensed Fukui Function. • Molecular docking studies are reported. [ABSTRACT FROM AUTHOR]