ARS | Publication request: B3lyp/6-311++g** Studies on Carbohydrates:effect of Explicit Water Molecules on the Conformation and Energies of Selected Mono and Disaccharides

Submitted to: Midwest Theoretical Chemistry Conference
Publication Type: Abstract
Publication Acceptance Date: May 9, 2003
Publication Date: June 12, 2003
Citation: MOMANY, F.A., APPELL, M.D., WILLETT, J.L. B3LYP/6-311++G** STUDIES ON CARBOHYDRATES:EFFECT OF EXPLICIT WATER MOLECULES ON THE CONFORMATION AND ENERGIES OF SELECTED MONO- AND DISACCHARIDES. MIDWEST THEORETICAL CHEMISTRY CONFERENCE. 2003. Abstract p. 80.

Technical Abstract: Optimization of cellobiose hydrates, and mono-, penta- and deca- hydrates of glucose were carried out at the B3LYP/6-311++G** level of theory. Enthalpy, entropy, zero point energy, and hydrogen bond energies and distances are reported. Favored patterns for the water configurations were found. Networks of hydrogen bonding are observed, and the occupation numbers for water hydrogen bonding examined. A new shorthand algorithm is described to help distinguish the positions of the water molecules around the carbohydrate molecule. Previous calculations on cellobiose and some cellobiose analogs showed that the most energetically stable conformation was one in which the dihedral angle phi was "flipped" by less than 180 degrees to the "normal" or observed form. To understand the above observation, cellobiose mono- and di-hydrates were studied. Preliminary studies suggest that more than two water molecules are required for the "normal" conformation of the hydrate to be energetically preferred over the "flipped" conformation.