Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2005
Publication Date: December 15, 2005
Citation: Momany, F.A., Willett, J.L., Appell, M.D., Bosma, W. 2005. DFT studies of hydrated carbohydrates:explicit water molecule around glucose and cellobiose geometry optimized at B3lYP/6-311++G** [abstract]. CD-ROM. International Chemical Congress of Pacific Basin. Technical Abstract: Water molecules have been placed around molecules of glucose and cellobiose, with geometry optimization carried out using the B3LYP density functional and 6-311++G** basis set level of theory. Electronic energy, zero point vibrational energy, enthalpy, entropy, hydrogen bonding energies, and relative free energies were obtained using an analytical Hessian. The relative anomeric stability of glucose was found to approach the experimental value favoring the beta anomer as more water was added. Cellobiose was shown to energetically prefer the "normal" conformation over the "flipped" form by less than 2 kcal/mol when up to three water molecules are added. Hydroxymethyl rotamer populations as well as geometry variances from X-ray diffraction data are described and explained. The calculated vibrational frequencies and NMR chemical shifts are presented with comparisons between configurations. At all stages comparison with experimental properties is made when appropriate data is available. Agreement with a variety of experimental parameters was excellent and a new understanding of carbohydrate/water interactions is described.