title: NBO analysis and vibrational spectra of 2,6-bis(p-methyl benzylidene cyclohexanone) using density functional theory.
abstract: Vibrational analysis of the 2,6-bis(p-methyl benzylidene cyclohexanone) [PMBC] compound was carried out by using NIR FT-Raman and FT-IR spectroscopic techniques. The equilibrium geometry, various bonding features and harmonic vibrational frequencies of PMBC have been investigated with the help of B3LYP/6-31 G(d) density functional theory method. The optimized geometry clearly demonstrates cyclohexanone ring chair conformation is changed into half-chair conformation. The shortening of C-H bond length and blue shifting of the CH stretching wavenumber suggest the existence of improper weak C-H***O hydrogen bonding, which is confirmed by the natural bond orbital analysis. The Mulliken population analysis on atomic charges and the HOMO-LUMO energy are also calculated.
authors.affiliation: Centre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College, Thiruvananthapuram 695015, Kerala, India.
authors.forename: L
authors.initials: L
authors.lastname: Padmaja
authors.forename: M
authors.initials: M
authors.lastname: Amalanathan
authors.forename: C
authors.initials: C
authors.lastname: Ravikumar
authors.forename: I
authors.initials: I
authors.lastname: Hubert Joe
mesh_terms: D003198:Computer Simulation; D003512:Cyclohexanones / Q000032:analysis*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D003512:Cyclohexanones