Synthesis of β-cyclodextrin derivative bearing a cyclohexylamino moiety and its inclusion complexation with organic dye molecules

Abstract

A novel β-cyclodextrin derivative bearing a cyclohexylamino moiety ( 3) was synthesized by reaction of cyclohexylamine with mono-[6- O-( p-tolylsulfonyl)]-β-cyclodextrin and its binding ability for 1:1 inclusion complexation with a series of naphthalene derivatives and AR was evaluated in phosphate buffer solution (pH=7.2, 0.1 mol dm −3) at 25°C by spectrofluormetric titrations. The results obtained indicate that the modification dramatically enhanced the original binding ability of natural β-cyclodextrin by a factor 2.52–28.4, except for 2-naphthalenesulfonic acid sodium (2-NS) and demonstrated that the pH values and salt intensity of the solution also directly influenced the molecular binding ability of the compound ( 3). The binding abilities and molecular selectivities of model substrates by modified β-cyclodextrin ( 3) are discussed from the viewpoints of size/shape-fit and geometry compensation between host cyclodextrins and guest dye molecules.