Pseudo[3]rotaxane Type Compelxation between ¦Á- and ¦Â-Cyc1odextrins and N,N?Dsiheptyl-4,4?bipyridinium

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• 作者：Iwao Suzuki and Akiyo Yamauchi
• 关键词：binding conformation ; cyclodextrin ; N ; N ; diheptyl ; 4 ; 4 ; bipyridinium ; p ; nitrophenol ; pseudorotaxane ; spectral displacement method
• 刊名：Journal of Inclusion Phenomena and Macrocyclic Chemistry
• 出版年：2006
• 出版时间：April, 2006
• 年：2006
• 卷：54
• 期：3-4
• 页码：193-200
• 全文大小：620.2 KB

文摘

Pseudo[3]rotaxane type complexation of α- and β-cyclodextrins (α- and β-CDs, respectively) with N,N′-Diheptyl-4,4′-bipyridinium (diheptyl viologen; HV2+) was investigated. A spectral displacement method using p-nitrophenol as a dye revealed that α-CD and HV2+ formed a 2:1 host-guest complex with stability constants being 3280 and 976 M−1 as the first and second steps of complexation, respectively. 1H-NMR spectra strongly indicated that α-CD accommodated the heptyl groups of HV2+. Although previous studies based on circular dichroism spectroscopy suggested the primary hydroxy side of α-CD faced to the positively charged bipyridinium moiety od HV2+, 2D-NMR studies clearly demonstrated that the secondary hydroxy side of α-CD faced to the bipyridinium moiety. β-CD also formed a 2:1 complex with HV2+ with a similar fashion.