| Abstrakt: |
Three novel bisβcyclodextrin CDs with flexible glycol linkers, i.e., ethylene glycolbridged bis6hydroxy6deoxyβCD 2, diethylene glycolbridged bis6hydroxy6deoxyβCD 3, and triethylene glycolbridged bis6hydroxy6deoxyβCD 4 have been synthesized by the reaction of mono6OptoluenesulfonylβCD with corresponding materials. The inclusion complexation behaviors of these compounds 2–4with organic dyes; that is, acridine red =N3Z6methylamino3Hxanthen3ylidenemethanaminium chloride; AR, neutral red =N8,N8,3trimethylphenazine2,8diamine hydrochloride; NR, ammonium 8anilinonaphthalene1sulfonate ANS, sodium 6ptoluidinylnaphthalene2sulfonate TNS, rhodamine B RhB and brilliant green =N44diethylaminocyclohexa2,5dien1ylphenylmethylcyclohex2en1ylideneNethylethanaminium hydrogen sulfate; BG, have been investigated at 25° in phosphate buffer pH7.20 by ultraviolet, fluorescence, and 2DNMR spectroscopy. The results indicate that the two linked CD units may cooperatively bind a guest, and the molecular binding ability toward dye guests, especially bent ANS, Tshaped RhB, and triangular BG, can be extended. This cooperative binding mode is confirmed by Jobs experiments and 2DNMR investigations. Furthermore, the complex stability depends greatly on the linker length of these glycolbridged bisβCDs and the size and shape of guest. The higher binding ability and selectivity of dye molecules by bisβCDs 2–4are discussed from the viewpoint of sizeshapefit concept and multiple recognition mechanism. [ABSTRACT FROM AUTHOR] |
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