A series of novel bis(β-cyclodextrin)s connected by organoselenium linkers, i.e., 6,6‘-trimethylenediseleno-bridged bis(β-cyclodextrin) (2), 2,2‘-trimethylenediseleno-bridged bis(β-cyclodextrin) (3), 6,6‘-o-phenylenediseleno-bridged bis(β-cyclodextrin) (4), and the corresponding platinum(IV) complexes (5−7) were synthesized from β-cyclodextrin (1). The inclusion complexation behavior of 1−7 with some fluorescent dyes, i.e., ammonium 8-anilino-1-naphthalenesulfonate, sodium 2-(p-toluidinyl)naphthalenesulfonate, Methyl Orange, and Mordant Orange 1, was investigated in aqueous phosphate buffer solution (pH 7.20) at 25 °C by fluorescence and circular dichroism spectrometry, as well as fluorescence lifetime measurements. The spectrofluorometric and spectropolarimetric titrations gave the complex stability constant (K S) and Gibbs free energy change (ΔG°) for the stoichiometric 1:1 inclusion complexation of 1−7 with the fluorescent dyes. The bis(β-cyclodextrin)s 2−4 showed higher affinities toward these guests than native β-cyclodextrin, and the binding abilities of 5−7 were further enhanced by incorporating Pt(IV). The cooperative binding abilities of these bis(β-cyclodextrin)s are discussed from the viewpoints of the size/shape-fit concept, the induced-fit interaction, and the multiple recognition mechanism.

A single crystal of mono(6-anilino-6-deoxy)-beta-cyclodextrin was prepared, and its crystal structure was determined by X-ray crystallographic analysis, which clearly revealed that the anilino groups are consecutively included intermolecularly into the adjacent cyclodextrin cavities in the crystal, thus giving rise to a consolidated column, located on a 2(1)-screw axis.

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