Theoretical Study of Covalently Bound 螒-Cyclodextrin Associations

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• 作者：Cleber P. A. Anconi ; Clebio S. Nascimento ; Jr. ; Wagner B. De Almeida ; H茅lio F. Dos Santos
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：September 6, 2012
• 年：2012
• 卷：116
• 期：35
• 页码：18958-18964
• 全文大小：440K
• 年卷期：v.116,no.35(September 6, 2012)
• ISSN：1932-7455

文摘

In the present work, the structures and relative energies of 108 linked 伪-cyclodextrin dimers have been evaluated at a quantum mechanics level of theory. Contrary to hydrogen-bonded associations, the covalently bound tail-to-tail (TT) arrangement has been identified as the most favorable, regardless of the number of cross-linking groups and their spatial topologies. On the basis of the study of 伪-cyclodextrin tetramers, the outcomes have been extended to small molecular oligomers, suggesting the relative number of TT arrangements as the primary feature to the stability of larger covalently bound 伪-cyclodextrin associations. Despite the TT stability, long molecular tubes possessing only such association cannot exist because many TT associations imply the existence of many HH associations. In this context, it can be stated that relative energy stability associated with spatial requirements accounts for the small HT population experimentally expected in molecular tubes.