Theoretical Studies of Molecular Structures, Infrared Spectra, NBO and NLO Properties of Some Novel 5-arylazo-6-hydroxy-4-phenyl-3-cyano-2-pyridone Dyes
A. Esmea and S.G. Sagdinc b
aDepartment of Elementary Science Education, Kocaeli University, 41380, Umuttepe, Kocaeli, Turkey
bDepartment of Physics, Science and Art Faculty, Kocaeli University, 41380, Umuttepe, Kocaeli, Turkey
Received: February 18, 2016; In final form: November 5, 2016
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The optimized geometrical structures, infrared spectra, molecular electrostatic potential, natural bond orbital and nonlinear optical properties of 5-phenylazo-6-hydroxy-4-phenyl-3-cyano-2-pyridoine (1) and 5-(4-bro-mophenylazo)-6-hydroxy-4-phenyl-3-cyano-2-pyridoine (2) dyes with a detailed study on the azo-hydrazone tautomerism in the ground state have been investigated by density functional theory using B3LYP functional with 6-31G(d,p) basis set. Vibrational modes are assigned with the help of vibrational energy distribution analysis program. Highest occupied molecular orbital and lowest unoccupied molecular orbital energies of the (1) and (2) compounds with azo and hydrazone forms were calculated with the same method and basis set. Molecular parameters like global hardness (η), global softness (σ) and electronegativity (χ) were calculated with the results obtained from the highest occupied and lowest unoccupied molecular orbital energies. Nonlinear optical parameters (mean polarizability (⟨α⟩), the anisotropy of the polarizability (⟨Δα⟩) and the mean first-order hyperpolarizability (⟨β⟩)) of the title compounds were investigated theoretically. The atomic charges, electronic exchange interaction, and charge delocalization of the molecules have been studied by natural bond orbital analysis.

DOI: 10.12693/APhysPolA.130.1273
PACS numbers: 31.15.E-, 33.20.Ea, 31.50.Bc, 42.65.-k