title: DFT studies of structure and vibrational spectra of 4-benzylidene-1-phenyl-2-selenomorpholino-1H-imidazol-5(4H)-one and its derivatives.
abstract: The Raman spectra and FT-IR spectra of 4-benzylidene-1-phenyl-2-selenomorpholino-1H-imidazol-5(4H)-one and its derivatives have been measured and their ground-state geometries and vibrational spectra are studied by DFT at B3LYP/6-31G(d) level. Comparing the optimized geometries of compounds 1-6, we find that different substituent and substitution site on benzene rings result in very small changes on the imidazoline skeleton, the changes on bond length are within 0.005 Å and on bond angle are within 0.5°. Calculated spectra are well consistent with the experimental one and the deviations are smaller than 30 cm-1. The influence of substituent on IR and Raman spectrum must not be neglected. Electron-withdrawing chlorine atom makes the stretching vibration of carbonyl group shift 4-16 cm(-1) towards higher wavenumber, but electron-donating methoxyl group and dioxole group make it shift 6-10 cm(-1) in IR and 9-13 cm(-1) in Raman spectrum towards lower wavenumber, respectively. Dioxole substitution makes the C=C stretching vibration of phenyl shift to a higher position at 1617-1618 cm(-1). The influence of intermolecular weak interaction on vibrational spectrum is studied by two models (dimer and monomer inclusion van del Waals correction). Dimer model presents a better accuracy, but van del Waals correction on B3LYP hybrid function does not produce a significant change on accuracy in this system.
authors.affiliation: School of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430073, China.
authors.forename: Shuli
authors.initials: S
authors.lastname: Zhou
authors.forename: Bin
authors.initials: B
authors.lastname: You
authors.forename: Qi
authors.initials: Q
authors.lastname: Yao
authors.forename: Meng
authors.initials: M
authors.lastname: Chen
authors.forename: Yujiao
authors.initials: Y
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Li
mesh_terms: D001597:Benzylidene Compounds / Q000737:chemistry; D019281:Dimerization; D007093:Imidazoles / Q000737:chemistry*; D016566:Organoselenium Compounds / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D001597:Benzylidene Compounds; D007093:Imidazoles; D016566:Organoselenium Compounds