Study on the Binding Ability of Mono-6-p-Nitrobenzoyl-β-Cyclodextrin with Naphthalene Derivatives in Aqueous Solution

To enhance the binding ability of β-cyclodextrin with naphthalene derivatives，a hydrophobic group to the rim of β-cyclodextrin was added and the new β-cyclodextrin compound—mono-6-p-nitrobenzoyl-β-cyclodextrin was synthesized. Its binding ability for 1: 1 inclusion complexation with 1-naphthoic acid was evaluated in the KCl/HCl buffer solution（pH=1.5，0.1 mol/dm3）at 15℃ by the spectrofluormetric titration. The results obtained indicated that mono-6-p-nitrobenzoyl-β-cyclodextrin could strongly include 1-naphthoic acid in aqueous solution；the modification dramatically enhanced the original binding ability of native β-cyclodextrin by a factor 9. The binding constants of mono-6-p-nitrobenzoyl-β-cyclodextrin and other naphthalenes such as 1-methoxynaphthalene，2-methoxynaphthalene，1-N，N-dimethylaminonaphthalene and 1-N，N-dimethylaminonaphthalene were obtained from the time-resolved fluorescence. The high binging ability of naphthalenes with NBCD make it is possible to assemble stable host-guest complexes.