ARS | Publication request: B3lyp/6-311++g**geometry Optimization of the Chair Forms of Alpha and Beta-D-Mannopyranose

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: March 17, 2004
Publication Date: July 4, 2004
Citation: Appell, M.D., Willett, J.L., Momany, F.A. 2004. B3lyp/6-311++g**geometry optimization of the chair forms of alpha- and beta-d-mannopyranose. Computational Chemistry Gordon Research Conference. Abstract no. 4.

Technical Abstract: Density functional calculations at the B3LYP/6-311++G** level of theory were carried out on the gg, gt and tg rotamers of the 4C1 and 1C4 chair conformations of mannopyranose in vacou. Several hydroxyl orientations were investigated. The structures of mannopyranose in the 4C1 chair conformation are less than 1.5 to 3 kcal/mol higher in overall energy than the lowest energy glucopyranose conformation that we have found. The 4C1 chair conformers of mannopyranose possess a slight preference for the beta-anomer over the alpha-anomer in vacou. The lowest energy conformation of mannopyranose in this study is the beta tg rotamer, however, other gg and gt rotamers of mannopyranose are within less than 0.3 kcal/mol in overall energy. While one low energy gg rotamer of beta-D-mannopyranose in the 1C4 chair conformation has been found, most 1C4 chair conformations in this investigation are less than 5-9 kcal/mol higher in energy than their 4C1 chair counterparts.