Location: Cotton Structure and Quality ResearchTitle: Conformational analysis of cellobiose by electronic structure theories Author
|French, Alfred - Al|
Submitted to: Carbohydrate Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2011
Publication Date: 1/3/2012
Citation: French, A.D., Johnson, G.P., Cramer, C., Csonska, G. 2012. Conformational analysis of cellobiose by electronic structure theories. Carbohydrate Research. 350:68-76. Interpretive Summary: Understanding the properties of cotton fabric and fiber ultimately requires understanding of the properties of the cellulose molecule that is the major component of cotton fiber. The cellulose molecule has been especially difficult to study by laboratory experiments because it occurs in very small crystals or in arrays that do not have regular order. Therefore, it is attractive to use theoretical methods that still give varying answers depending on just what method was used. This paper reports the most extensive study done with quantum mechanics theory to show among other things how water might affect the shape of the cellulose molecule. This was done by studying the shortest cellulose molecule that is composed of only two glucose molecules. The most probable structures were also studied with the Quantum Theory of Atoms in Molecules. This theory detects new interactions between atoms that stabilize certain shapes of the molecule.
Technical Abstract: Adiabatic phi/psi maps for cellobiose were prepared with B3LYP density functional theory. A mixed basis set was used for minimization, followed with 6-31+G(d) single-point calculations, with and without SMD continuum solvation. Different arrangements of the exocyclic groups (3starting geometries) were considered for each phi/psi point. The vacuum calculations agreed with earlier computational and experimental results on the preferred gas phase conformation and the results from the solvated calculations were consistent with the conformations from condensed phases (crystals or solutions). Results from related studies were compared, and there is substantial dependence on the solvation model as well as arrangements of exocyclic groups. New stabilizing interactions were revealed by Atoms-In-Molecules theory.