title: Fourier transform-infrared and Raman spectra, ab initio calculations and assignments for 6-methyl-4-bromomethylcoumarin.
abstract: Fourier transform-infrared (4000-400 cm-1) and Raman (3500-50 cm-1) spectral measurements have been made for 6-methyl-4-bromomethylcoumarin. Equilibrium structures, harmonic vibrational frequencies, infrared intensities, and depolarization ratios have been computed at RHF/6-31G* and B3LYP/6-31G* levels of theory. Twisting CH2Br moiety in the geometry optimization leads to the most stable conformer lacking symmetry (C1). This is reflected in the richness of bands in the experimental spectra. A complete assignments of the bands, aided by the ab initio calculations, has been proposed for the 6-methyl-4-bromomethylcoumarin. Due to lack of symmetry, several normal vibrations have been found to be mixed ones.
authors.affiliation: Department of Physics, Karnatak University, Pawate Nagar, Dharwad 580003, India.
authors.forename: Veenasangeeta
authors.initials: V
authors.lastname: Sortur
authors.forename: Jayashree
authors.initials: J
authors.lastname: Yenagi
authors.forename: J
authors.initials: J
authors.lastname: Tonannavar
authors.forename: V B
authors.initials: VB
authors.lastname: Jadhav
authors.forename: M V
authors.initials: MV
authors.lastname: Kulkarni
mesh_terms: D003374:Coumarins / Q000737:chemistry*; D008956:Models, Chemical; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014732:Vibration
chemical_list: C512531:6-methyl-4-bromomethylcoumarin; D003374:Coumarins; C018096:6-methylcoumarin