title: Vibrational spectroscopic and DFT calculation studies of 2-amino-7-bromo-5-oxo-[1]benzopyrano [2,3-b]pyridine-3 carbonitrile.
abstract: The vibrational spectra of 2-amino-7-bromo-5-oxo-[1]benzopyrano [2,3-b]pyridine-3 carbonitrile were recorded using fourier transform-infrared and fourier transform-Raman spectrometer. The optimized structural parameters, vibrational frequencies, Mulliken atomic charge distribution, frontier molecular orbitals, thermodynamic properties, temperature dependence of thermodynamic parameters, first order hyperpolarizability and natural bond orbital calculations of the molecule were performed using the Gaussian 09 program. The vibrational frequencies were assigned on the basis of potential energy distribution calculation using the VEDA 4.0 program. The calculated first order hyperpolarizability of ABOBPC molecule was obtained as 6.908×10(-30) issue, which was 10.5 times greater than urea. The nonlinear optical activity of the molecule was also confirmed by the frontier molecular orbitals and natural bond orbital analysis. The frontier molecular orbitals analysis shows that the lower energy gap of the molecule, which leads to the higher value of first order hyperpolarizability. The natural bond orbital analysis indicates that the nonlinear optical activity of the molecule arises due to the π→π(∗) transitions. The Mulliken atomic charge distribution confirms the presence of intramolecular charge transfer within the molecule. The reactive site of the molecule was predicted from the molecular electrostatic potential contour map. The values of thermo dynamic parameters were increasing with increasing temperature.
authors.affiliation: Department of Physics, N.M.S.S.V.N. College, Madurai 625 019, Tamil Nadu, India.
authors.forename: S
authors.initials: S
authors.lastname: Premkumar
authors.affiliation: Department of Chemistry, N.M.S.S.V.N. College, Madurai 625 019, Tamil Nadu, India.
authors.forename: A
authors.initials: A
authors.lastname: Jawahar
authors.affiliation: Department of Physics, N.M.S.S.V.N. College, Madurai 625 019, Tamil Nadu, India.
authors.forename: T
authors.initials: T
authors.lastname: Mathavan
authors.affiliation: Department of Physics, N.M.S.S.V.N. College, Madurai 625 019, Tamil Nadu, India.
authors.forename: M
authors.initials: M
authors.lastname: Kumara Dhas
authors.affiliation: Department of Physics, N.M.S.S.V.N. College, Madurai 625 019, Tamil Nadu, India. Electronic address: miltonfranklin@yahoo.com.
authors.forename: A
authors.initials: A
authors.lastname: Milton Franklin Benial
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009570:Nitriles / Q000737:chemistry*; D016011:Normal Distribution; D055095:Optics and Photonics; D011725:Pyridines / Q000737:chemistry*; D011789:Quantum Theory; D012984:Software; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013696:Temperature; D013816:Thermodynamics; D014732:Vibration
chemical_list: C000604130:2-amino-7-bromo-5-oxo-(1)benzopyrano(2,3-b)pyridine-3 carbonitrile; D001578:Benzopyrans; D009570:Nitriles; D011725:Pyridines; C509176:pyridine-3-carbonitrile
keywords: Density functional theory studies; First order hyperpolarizability; Frontier molecular orbitals; Natural bond orbital; Thermo dynamic parameters; Vibrational analysis