Quantum mechanical and spectroscopic ( FT - IR , FT - Raman , 1 H NMR and UV ) investigations of 2 - ( p - nitrobenzyl ) benzoxazole

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 2(p-nitrobenzyl)benzoxazole have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of vibrations are done using GAR2PED program. The optimized geometrical parameters are in agreement with that of similar derivatives. The energy and oscillator strength calculated by Time Dependent Density Functional Theory results almost compliments with experimental findings. Gauge-including atomic orbital H NMR chemical shifts calculations were carried out by using B3LYP functional with 6-31G basis sets. The HOMO and LUMO analysis is used to determine the charge transfer with in the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. MEP was performed by the DFT method and the infrared and Raman intensities have also been reported. Mulliken’s net charges have been calculated and compared with the atomic natural charges. The calculated first hyperpolarizability of the title compound is 82.31 time that of the standard NLO material urea and hence is an attractive object for future studies of nonlinear optical properties. 2013 Elsevier B.V. All rights reserved.