A reinvestigation of the molecular structures, vibrations and rotation of methyl group in o-methylaniline in S0 and S1 states studied by laser induced fluorescence spectroscopy and ab initio calculations.
The UV fluorescence excitation and dispersed fluorescence spectra of a jet-cooled o-methylaniline have been obtained for the S1 <-- S0 transition, in which some of the bands have been observed and assigned for the first time. The origin of the electronic transition appears at 34,328.4 cm(-1). It was found that the spectra exhibit an important feature corresponding to the internal rotation of the methyl group in the electronic ground and excited states. Ab initio calculations at MP2/6-31 + G* and CIS/6-31 + G* show that the optimised structure of o-methylaniline in the ground state is not planar with the amino group having sp3 hybridation-like character due to the existence of lone paired electrons on the N atom. Upon electronic excitation, the C-N bond exhibits a partial double character, as in the case of other aniline derivatives.
Ballesteros
B
B
Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Castilla-La Mancha, Ciudad Real, Spain. bballest@qifi-cr.uclm.es
Santos
L
L
D000465:Algorithms; D000814:Aniline Compounds / Q000032:analysis* / Q000737:chemistry*; D055592:Biophysical Phenomena; D001703:Biophysics; D008956:Models, Chemical; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014466:Ultraviolet Rays
D000814:Aniline Compounds; C021313:methylaniline