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Vibrational molecular force field of model compounds with biologic interest. II. Harmonic dynamics of both anomers of glucose in the crystalline state
Author(s) -
Dauchez Manuel,
Derreumaux Philippe,
Vergoten Gérard
Publication year - 1993
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540140303
Subject(s) - intramolecular force , chemistry , intermolecular force , force field (fiction) , potential energy , dielectric , molecule , anomer , computational chemistry , molecular dynamics , atomic physics , stereochemistry , physics , quantum mechanics , organic chemistry
Combining the modified Urey–Bradley–Shimanouchi intramolecular potential energy function with an appropriate intermolecular energy function, normal coordinate calculations have been performed for both α and β anomers of glucose and for some deuterated analogs in the crystalline state. The overall agreement between the observed and calculated frequencies leads to an average error on the order of 3 and 5 cm −1 for α and β glucose, respectively. In both cases, it is shown that the intermolecular potential energy terms are essential to reproduce perfectly the whole spectra, in particular for the hydroxyl stretching region, the anomeric and crystalline spectral regions, and the low‐frequency range. Moreover, the intermolecular interactions have a nonnegligible influence on the value of the intramolecular force constants. But, the potential energy distribution of vibrational modes are in accord with previous works performed for an isolated molecule. It is also important to point out that approximately the same set of force constants has been used for both molecules, differences existing only for the atoms involved in the anomeric configuration. Likewise, different charge distributions have been calculated and tested with different value of the dielectric constant. Charges determined by the AM 1 quantum mechanical procedure with a value of 3 for the dielectric constant have the merit to reproduce quite well the whole spectra and in particular the frequency range below 200 cm −1 . © 1993 John Wiley & Sons, Inc.