The non-bonded interactions in D-glucose and β-maltose: an ab initio study of conformations produced by empirical force-field calculations

Abstract

Minimal basis set SCF-MO computations on conformations of α- D-gluco-pyranose, β- D-glucopyranose, and β-maltose resulting from empirical energy minimisation reproduce known trends in relative energy. Analysis of electron population and molecular orbital valency-state energy leads to separation of atoms into classes, two for oxygen, three for carbon, and two for hydrogen, the classes being correlated with the chemical environments of the atoms. Partitioning of the total energy into two-centre terms gives a quantification of non-bonded interactions, leading to potential energy curves for interactions of all types of atom present. Peculiar details of the electronic structure at and around the anomeric carbon atoms are noted: C(1s) chemical shift is insensitive to configuration, but depends on conformation.