Vibrational (FT-IR and FT-Raman) spectra and quantum chemical studies on the molecular structure of p-hydroxy-N-(p-methoxy benzylidene) aniline

Abstract

The FT-IR and FT-Raman spectra of p-hydroxy-N-(p-methoxy benzylidene) aniline have been recorded in the region 4000-400 cm⁻¹ and 3500-100 cm⁻¹, respectively. The optimized molecular geometry, vibrational frequencies in ground state have been calculated using density functional B3LYP methods (DFT) with 6-31+G(d,p) and 6-311++G(d,p) basis sets. The observed FT-IR and FT-Raman vibrational frequencies have been analysed and compared with theoretically predicted vibrational frequencies. The geometries and normal modes of vibration obtained from B3LYP/6-311+G(d,p) and B3LYP/6-311++G(d,p) methods are reliable compared with the experimental data. The natural bonding orbital (NBO) analysis of the investigated molecule have been computed using DFT/ B3LYP/6-311++G(d,p) calculations. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule.