Selective binding of chiral molecules of cinchona alkaloid by beta- and gamma-cyclodextrins and organoselenium-bridged bis(beta-cyclodextrin)s.
The inclusion complexation behavior of chiral members of cinchona alkaloid with beta- and gamma-cyclodextrins (1 and 2) and 6,6(')-trimethylenediseleno-bridged bis(beta-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 degrees 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 beta-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.
Liu
Yu
Y
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, PR China. yuliu@public.tpt.tj.cn
Li
Li
L
Zhang
Heng-Yi
HY
Fan
Zhi
Z
Guan
Xu-Dong
XD
D001665:Binding Sites; D002930:Cinchona Alkaloids / Q000737:chemistry* / Q000145:classification; D003505:Cyclodextrins / Q000737:chemistry*; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D016566:Organoselenium Compounds / Q000737:chemistry; D012643:Selenium / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013237:Stereoisomerism; D047392:beta-Cyclodextrins; D047408:gamma-Cyclodextrins
D002930:Cinchona Alkaloids; D003505:Cyclodextrins; D046911:Macromolecular Substances; D016566:Organoselenium Compounds; D047392:beta-Cyclodextrins; D047408:gamma-Cyclodextrins; C415746:selenium-bridged-6,6'-amino-selenocystine-6,6'-deoxy-di-beta-cyclodextrin; D012643:Selenium; C031215:betadex; C023792:gamma-cyclodextrin