Abstract: Spectrofluorometric and spectrophotometric titrations were performed in aqueous buffer solution at₂5 ℃ to give the complex stability constants for the stoichiometric 1∶1 inclusion complexation of β-cy-clodextrin( β-CD, 1), hydroxypropyl β cyclodextrin(HP-β-CD, 2) and 2,3,6-tri-O-methyl-β-cyclodextrin(MO-β-CD, 3) with six aliphatic chiral guests and four dyes. The molecular binding ability and selectivity of cyclodextrins 1—3 toward guests were discussed from the size/shape fit concept between hosts and guests. The results obtained indicate that hydrophobic and hydrogen bond interactions play an important role in the inclusion complexation of cyclodextrins 1—3, and the substituents introduced alter the original hydrophobicity of cavity and the molecular binding ability of β-cyclodextrin.

Key words: β-Cyclodextrin, Chiral molecule, Dyes, Molecular recognition