Synthesis of L-cystine bridged bis(p-cyclodextrin) and its cooperative binding toward guest molecules
Synthesis of L-cystine bridgedbis（β-cyclodextrin） and its cooperative binding toward guest molecules

A novel β-cyclodextrin derivative, L-cystine bridged bis(β-cyclodextrin) 1 has been synthesized and characterized by1H NMR,13C NMR, IR, Raman and combustion analyses. Spectrofluorometric titrations have been performed in aqueous phosphate buffer solution (pH=7.20) at 25 °C to give the complex stability constants (KS) and Gibbs free energy changes ( ΔG°) for the stoichiometric 1:1 inclusion complexation of 1 with four dyes. The binding abilities and molecular selectivities are discussed from the viewpoint of size/shape-fit and electrostatic interactions between hosts and guests. 2D ROESY investigation for the complexation between host and guest further confirms the cooperative binding of bridged cyclodextrin 1 with guest.