Vibrational analysis of 3-diazo-2-butanone. Infrared and raman spectra: calculated normal modes of CH 3COCN 2CH 3 and CD 3COCN 2CD 3

Abstract

The infrared (gas, liquid, solution, Kr matrix) and Raman (liquid) spectra of s-E CH 3COCN 2CH 3 and CD 3COCN 2CD 3 are studied between 3200 and 100 cm −1. A vibrational assignment is given, which is consistent with both the IR rotation—vibration band shapes and Raman depolarization data as with matrix trapping site effects. The assignment is supported by a theoretical prediction of the fundamental frequencies calculated with a zero order valence force field transferred from s-Z diazo-2-propanone for which a preliminary GVFF normal modes calculation is performed from previously assigned fundamental frequencies. After refinement of the force constants, the new force field is used to predict the vibrational spectrum of a folded conformer of 3-diazo-2-butanone s-Z.