|Bosma, Wayne - BRADLEY UNIV/CHEM DEPT|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 12, 2007
Publication Date: August 16, 2007
Citation: Bosma, W., Schnupf, U., Willett, J.L., Momany, F.A. 2007. DENSITY FUNCTIONAL CALCULATION OF ENERGIES AND VIBRATIONAL FREQUENCIES OF GLUCOSE AND GLUCOSE-WATER COMPLEXES: WATER PLACEMENT AND GLUCOSE CONFORMATIONAL EFFECTS ON THE CALCULATED INFRARED SPECTRUM. Meeting Abstract. xx. Technical Abstract: The structures and energies of glucose and glucose monohydrates have been calculated at the B3LYP/6-311++G** level of theory. Both the alpha and beta anomers were studied, with all possible combinations of hydroxymethyl rotamer (gg, gt, or tg) and hydroxyl orientation (clockwise or counter-clockwise). Redshifts in the OH stretch peaks characteristics of alpha anomers and tg rotamers have been identified. Monohydrates have been studied for all conformers and rotamers, placing the water molecule at all possible single-donor single-acceptor hydrogen bonding sites. A new global minimum has been identified for glucose monohydrates, corresponding to a structure that requires little distortion of the glucose structure in order to accommodate the water molecule. In the monohydrates, the water OH stretching motions couple to the glucose vibrations at the hydrogen-bond donor site, giving redshifted peaks characteristic of the glucose-water hydrogen bonds. The extent to which these peaks are conformation-dependent depends strongly on the location of the water molecule. Different spectral "signatures" associated with the various rotamers and water locations were found. Comparison is made to recent gas-phase spectroscopic experiments on glucose derivatives and their hydrates.