Aggregation and Host鈥揋uest Interactions in Dansyl-Substituted Poly(acrylate)s in the Presence of 尾-Cyclodextrin and a 尾-Cyclodextrin Dimer in Aqueous Solution: A UV鈥揤is, Fluorescence, 1H NM

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• 作者：Jie Wang ; Duc-Truc Pham ; Tak W. Kee ; Scott N. Clafton ; Xuhong Guo ; Philip Clements ; Stephen F. Lincoln ; Robert K. Prud鈥檋omme ; Christopher J. Easton
• 刊名：Macromolecules
• 出版年：2011
• 出版时间：December 27, 2011
• 年：2011
• 卷：44
• 期：24
• 页码：9782-9791
• 全文大小：1165K
• 年卷期：v.44,no.24(December 27, 2011)
• ISSN：1520-5835

文摘

A UV鈥搗is, steady-state, and time-resolved fluorescence 2D ¹H NOESY NMR spectroscopic and rheological study of new poly(acrylate)s 3% randomly substituted with either N-(2-aminoethyl)-, N-(6-aminohexyl)-, or N-(12-aminododecyl)-5-dansyl-sulfonamide to give the substituted polymers PAADSen, PAADShn, and PAADSddn, respectively, is reported. Their dansyl substituent aggregation and complexation by 尾-cyclodextrin, 尾CD, and its covalently linked dimer N,N鈥?bis(6^A-deoxy-6^A-尾-cyclodextrin)urea, 66尾CD₂ur, is also reported. The 尾CD complexation of the dansyl substituents is characterized by apparent complexation constants, K = 89, 105, and 55 dm³ mol^鈥? for PAADSen, PAADShn, and PAADSddn, respectively, and the analogous complexations by 66尾CD₂ur are characterized by K = 3.04 脳 10³, 3.42 脳 10⁴, and 2.42 脳 10⁵ dm³ mol^鈥? at pH 7.0 in aqueous 0.10 mol dm^鈥? NaCl at 298.2 K. Under the same conditions the dansyl substituent shows three fluorescence decay constants assigned to the aggregated (蟿₁ = 2.2, 2.5, and 3.2 ns), single (蟿₂ = 5.0, 5.3, and 9.5 ns), 尾CD (蟿₃ = 13.2, 11.7 ns, and undetected), and 66尾CD₂ur complexed dansyl substituent states (蟿₃ = 13.9, 20.8, and 19.3 ns) where the values in each data set correspond to PAADSen, PAADShn, and PAAddn solutions, respectively. 2D ¹H NOESY NMR spectroscopy provides additional insight into dansyl substituent complexation by 尾CD and 66尾CD₂ur, as do rheological studies. These data are interpreted in terms of the factors affecting dansyl substituent fluorescence quenching and the impact of tether length on dansyl substituent aggregation, complexation, and network formation.