H-Bond Isomerization in Crystalline Cellulose IIII: Proton Hopping versus Hydroxyl Flip-Flop

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• 作者：Pan Chen ; Mateusz Marianski ; Carsten Baldauf
• 刊名：ACS Macro Letters
• 出版年：2016
• 出版时间：January 19, 2016
• 年：2016
• 卷：5
• 期：1
• 页码：50-54
• 全文大小：358K
• ISSN：2161-1653

文摘

Based on density-functional theory calculations, we discuss three forms of cellulose III_I that are characterized by different intersheet H-bonding patterns. Two alternative mechanisms can facilitate the interconversion between these H-bonding patterns: the rotation of hydroxy groups (“flip-flop”) or a concerted proton transfer from one hydroxy group to the other (“proton hopping”). Both mechanisms have energy barriers of very similar height. Electronic structure theory methods allow us to study effects that involve the breaking/forming bonds, like the hopping of protons. In many of the force field formulations, in particular, the ones that are typically used to study cellulose, such effects are not considered. However, such insight at the atomistic and electronic scale can be the key to finding energy-efficient means for cellulose deconstruction.