Abstract
The hydrogen bond arrangement in a complex of cellulose with ammonia has been studied using neutron crystallography in combination with molecular dynamics simulations. The O6 atom of the hydroxymethyl group is donor in a highly occupied hydrogen bond to an ammonia molecule. This rotating ammonia molecule is donor in partially occupied and transient hydrogen bonds to the O2, O3 and O6 atoms of the hydroxyl groups of other chains. The hydrogen atom bound to the O3 atom is disordered but it is almost always involved in some type of hydrogen bonding. It is donated in a hydrogen bond most of the time to the O5 atom on the same chain. However, it also rotates away from this O5 atom to be donated to an ammonia molecule part of the time. On the other hand the hydrogen atom bound to the O2 atom is free from hydrogen bonding most of the time. It is donated in a hydrogen bond to the O6 atom on a neighboring chain only with a relatively small probability. These results provide new insights into how hydrogen bonds are rearranged during the conversion of cellulose I to cellulose IIII by ammonia treatment.
| Original language | English |
|---|---|
| Pages (from-to) | 191-206 |
| Number of pages | 16 |
| Journal | Cellulose |
| Volume | 18 |
| Issue number | 2 |
| DOIs | |
| State | Published - Apr 2011 |
| Externally published | Yes |
Funding
Acknowledgments We thank beam line D19 at the Institute Laue Langevin for use of facilities. MW was supported by a Grant-in-Aid for Scientific Research (18780131). This study was partly funded by the French Agence Nationale de la Reserche. PL was supported in part by the Office of Biological and Environmental Research of the U.S. Department of Energy and a Laboratory Directed Research and Development grant from Los Alamos National Laboratory (20080001DR). GB thanks Don Thompson and CNLS at Los Alamos National Laboratory for (crucial) Information Technology support.
Keywords
- Ammonia treatment
- Cellulose
- Hydrogen bonding
- Molecular dynamics
- Neutron diffraction