Spectroscopic behaviour, bond properties and charge distribution in methoxy groups in hydrofluoroethers:: the effect of neighbouring CF2 group

A theoretical investigation is presented aimed to the interpretation of the spectroscopic behaviour of the methoxy group in molecules belonging to the class of hydrofluoroethers. The simulation of infrared and Raman spectra of four different stable conformers of CH3-O-CF2-CF2-O-CH3 and the comparison with the experimental spectra allow to propose a vibrational band assignment in the CH stretching region. This clarifies the role of the CF2 group in determining the electronic properties and spectroscopic parameters of methyl CH bonds when back-donation of electronic charge take place from oxygen. (C) 2004 Elsevier B.V. All rights reserved.