Selective binding of chiral molecules of cinchona alkaloid by β- and γ-cyclodextrins and organoselenium-bridged bis(β-cyclodextrin)s

• Published in: Bioorganic chemistry 2003-02, Vol.31 (1), p.11-23
• Main Authors: Liu, Yu, Li, Li, Zhang, Heng-Yi, Fan, Zhi, Guan, Xu-Dong
• Format: Article
• Language: English
• Subjects: 2D-NMR; beta-Cyclodextrins; Binding Sites; Chiral molecule; Cinchona alkaloid; Cinchona Alkaloids - chemistry; Cinchona Alkaloids - classification; Cooperative binding; Cyclodextrins; Cyclodextrins - chemistry; Fluorescence; gamma-Cyclodextrins; Inclusion complexation; Macromolecular Substances; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Conformation; Molecular recognition; Organoselenium; Organoselenium Compounds - chemistry; Selenium - chemistry; Sensitivity and Specificity; Spectrometry, Fluorescence; Stability constants; Stereoisomerism
• ISSN: 0045-2068; 1090-2120
• DOI: 10.1016/S0045-2068(02)00512-6

The inclusion complexation behavior of chiral members of cinchona alkaloid with β- and γ-cyclodextrins ( 1 and 2) and 6,6 ′-trimethylenediseleno-bridged bis(β-cyclodextrin) ( 3) was assessed by means of fluorescence and 2D-NMR spectroscopy. The spectrofluorometric titrations have been performed in aqueous buffer solution (pH 7.20) at 25.0 °C to determine the stability constants of the inclusion complexation of 1– 3 with guest molecules (i.e., cinchonine, cinchonidine, quinine, and quinidine) in order to quantitatively investigate the molecular selective binding ability. The stability constants of the resulting complexes of 2 with guest molecules are larger than that of 1. As a result of cooperative binding, the stability constants of inclusion complexation of dimeric β-cyclodextrin 3 with cinchonidine and cinchonine are higher than that of parent 1 by factor of 4.5 and 2.4, respectively. These results are discussed from the viewpoint of the size-fit and geometric complementary relationship between the host and guest.