Theoretical vibrational spectroscopy and the structure of nitrosubstituted glucopyranosides

Coupled calculations have been carried out of normal vibration frequencies from the point of view of the valence-force field scheme and of absolute IR band intensities by the CNDO/2 method for the 2,3-di-O-nitro-methyl-beta -D-glucopyranoside and 2,3,6-tri-O-nitro-methyl-beta -D-glucopyranoside molecules. A good agreement with experiment has been achieved. A detailed interpretation of the observable IR spectra of both the nitro-glucopyranosides compounds considered is given. Regularities of formation of complex absorption bands of characteristic vibrations of nitro-groups have been established. (C) 2000 Elsevier Science B.V. All rights reserved.