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Fluorescence Sensing and Selective Binding of a Novel 4,4′‐Sulfonyldianiline‐Bridged Bis( β ‐cyclodextrin) for Bile Salts
Author(s) -
Zhao Yan,
Yang Yong Cun,
Chi Shao Ming,
Shi Hao,
Zhao Yong,
Zhu Hong You,
Li Qi Lin,
Wang Yu Fei
Publication year - 2010
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200900327
Subject(s) - chemistry , moiety , fluorescence , linker , cyclodextrin , chelation , stereochemistry , selectivity , fluorescence spectroscopy , crystallography , organic chemistry , physics , quantum mechanics , computer science , catalysis , operating system
A novel 4,4′‐sulfonyldianiline‐bridged bis( β ‐cyclodextrin (CD)) 2 was synthesized, and its complex stability constants ( K s ) for the 1 : 1 inclusion complexation with bile salts, i.e. , cholate (CA), deoxycholate (DCA), glycocholate (GCA), and taurocholate (TCA) have been determined in phosphate buffer (pH 7.2) at 25° by fluorescence spectroscopy. The result indicated that 2 can act as efficient fluorescent sensor and display remarkable fluorescence enhancement upon addition of optically inert bile salts. Structures of the inclusion complexes between bile salts and 2 were elucidated by 2D‐NMR experiments, indicating that the anionic tail group and the D ring of bile salts penetrate into one CD cavity of 2 from the wide opening deeply, while the phenyl moiety of the CD linker is partially self‐included in the other CD cavity to form a host–linker–guest binding mode. As compared with native β ‐CD 1 upon complexation with bile salts, bis( β ‐CD) 2 enhances the binding ability and molecular selectivity. Typically, 2 gives the highest K s value of 26200 M −1 for the complexation with CA, which may be ascribed to the simultaneous contributions of hydrophobic, H‐bond, and electrostatic interactions. These phenomena are discussed from the viewpoints of multiple recognition and induce‐fit interactions between host and guest.