Crystal structure and hydrogen bonding system in cellulose I(alpha) from synchrotron X-ray and neutron fiber diffraction

J Am Chem Soc. 2003 Nov 26;125(47):14300-6. doi: 10.1021/ja037055w.

Abstract

The crystal and molecular structure, together with the hydrogen-bonding system in cellulose I(alpha), has been determined using atomic-resolution synchrotron and neutron diffraction data recorded from oriented fibrous samples prepared by aligning cellulose microcrystals from the cell wall of the freshwater alga Glaucocystis nostochinearum. The X-ray data were used to determine the C and O atom positions. The resulting structure is a one-chain triclinic unit cell with all glucosyl linkages and hydroxymethyl groups (tg) identical. However, adjacent sugar rings alternate in conformation giving the chain a cellobiosyl repeat. The chains organize in sheets packed in a "parallel-up" fashion. The positions of hydrogen atoms involved in hydrogen-bonding were determined from a Fourier-difference analysis using neutron diffraction data collected from hydrogenated and deuterated samples. The differences between the structure and hydrogen-bonding reported here for cellulose I(alpha) and previously for cellulose I(beta) provide potential explanations for the solid-state conversion of I(alpha) --> I(beta) and for the occurrence of two crystal phases in naturally occurring cellulose.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cellulose / chemistry*
  • Crystallography, X-Ray
  • Eukaryota / chemistry
  • Fourier Analysis
  • Hydrogen Bonding
  • Models, Molecular
  • Neutron Diffraction
  • Synchrotrons
  • X-Ray Diffraction

Substances

  • Cellulose