DANSYL-MODIFIED CYCLODEXTRINS AS FLUORESCENT CHEMOSENSORS FOR MOLECULAR RECOGNITION

alpha-, beta-, and gamma-cyclodextrin derivatives (cyclodextrin is abb reviated as CD, hereafter) bearing an dansyl or dansylglycine moiety a t the primary or secondary side of CD were synthesized as fluorescent indicators for molecular recognition. The CDs with the moiety at the s econdary hydroxy side have an asymmetric cavity with a distorted CD fr amework because of the conversion of one glucose member to an altrose residue and the effects of this distortion of the CD ring on the sensi ng abilities were examined, compared with the case of symmetrical CDs bearing the dansyl moiety at the primary side. The results demonstrate that the asymmetrical CDs are unfavorable to accommodate the guest sp ecies due to the cavity narrowed by the distortion, contrasting with t he observation that the symmetrical CDs exhibit remarkable sensing abi lities for various guests.