Journal Article10.1021/JA0257319
Crystal Structure and Hydrogen-Bonding System in Cellulose Iβ from Synchrotron X-ray and Neutron Fiber Diffraction
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TL;DR: In this article, the crystal and molecular structure of cellulose Iβ were determined using synchrotron and neutron diffraction data recorded from oriented fibrous samples prepared by aligning cellulose microcrystals from tunicin.
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Abstract: The crystal and molecular structure together with the hydrogen-bonding system in cellulose Iβ has been determined using synchrotron and neutron diffraction data recorded from oriented fibrous samples prepared by aligning cellulose microcrystals from tunicin. These samples diffracted both synchrotron X-rays and neutrons to better than 1 A resolution (>300 unique reflections; P21). The X-ray data were used to determine the C and O atom positions. The resulting structure consisted of two parallel chains having slightly different conformations and organized in sheets packed in a “parallel-up” fashion, with all hydroxymethyl groups adopting the tg conformation. 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 hydrogen atoms involved in the intramolecular O3···O5 hydrogen bonds have well-defined positions, whereas those corresponding to O2 and O6 covered a wider v...
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Citations
WAXS and 13C NMR study of Gluconoacetobacter xylinus cellulose in composites with tamarind xyloglucan.
TL;DR: The presence of xyloglucan has a profound effect on the formation of the cellulose crystallites by G. xylinus, and when the composites were refluxed in buffer, the proportion of cellulose I(beta) allomorph increased relative to that of cellulOSE I(alpha).
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Anion Bridging-Induced Structural Transformation of Cellulose Dissolved in Ionic Liquid.
TL;DR: Structural investigations of cellulose mixed with 1-ethyl-3-methylimidazolium acetate in the entire concentration range by wide-angle X-ray scattering with the aid of quantum chemical calculations and 13C solid-state NMR spectroscopy find a transformation into ordered layers where OAc anions and Emim cations intercalate.
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