CELL 179 |
| Using force field methods in combination with the semi-empirical bond polarization theory (BPT) it is possible for the first time to refine complete crystal structures using 13C NMR chemical shifts. This method was applied to the structure elucidation of cellulose polymorphs I a, I ©¬, and II. In the case of bacterial cellulose Ia the solid state NMR assignments of the 13C resonances were reinvestigated by INADEQUATE experiments. Additionally, we determined the principal chemical shift tensor components of each 13C labeled site from a 2D iso-aniso RAI (Recoupling of Anisotropy Information) spectrum (Figure: 2D-RAI-spectrum and the 13C chemical shift tensors of cellulose Ia). Based on these NMR data, the crystal structure of cellulose Ia was refined using the 13C chemical shifts for target functions.
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Structure and Properties of Cellulosic Polymers, Assemblies, and Nanocomposites
8:00 AM-11:45 AM, Tuesday, April 8, 2008 Morial Convention Center -- Rm. R07, Oral
Division of Cellulose & Renewable Materials |
