Combining computational chemistry and crystallography for a better understanding of the structure of cellulose

Authors: French, Alfred - Al

Submitted to: Advances in Carbohydrate Chemistry and Biochemistry
Publication Type: Book / Chapter
Publication Acceptance Date: 3/15/2012
Publication Date: 7/18/2012
Citation: French, A.D. 2012. Combining computational chemistry and crystallography for a better understanding of the structure of cellulose. Advances in Carbohydrate Chemistry and Biochemistry. 67:19-93.

Interpretive Summary: To make further progress in the efficient utilization of nature’s most abundant raw material, cellulose, further knowledge of its fundamental molecular structure is needed. Direct experiments on cellulose, and especially cotton cellulose, do not provide much data, and studies of related small molecules and theoretical studies are important ways to gain new information. This chapter covers progress in the understanding of four areas: The relationship of the molecular shapes of small molecules in crystals to cellulose, the use of computational chemistry to predict molecular shapes, the calculation of diffraction patterns from computer models of cellulose crystals, and the study of atom-to-atom interactions both by advanced experiments with X-rays and with computational chemistry.

Technical Abstract: The approaches in this article seek to enhance understanding of cellulose at the molecular level, independent of the source and the particular crystalline form of cellulose. Four main areas of structure research are reviewed. Initially the molecular shape is inferred from the crystal structures of many small molecules that have '-(1'4)-linkages. Then, conformational analyses with potential energy calculations of cellobiose are covered, followed by the use of Atoms-In-Molecules theory to learn about interactions in experimental and theoretical structures. The last section covers models of cellulose nanoparticles. Controversies addressed include the stability of two-fold screw-axis conformations, the influence of different computational methods, the predictability of crystalline conformations by studies of isolated molecules, and the twisting of model cellulose crystals.