Fluorescent pyrrolinone-modified cyclodextrins as a chemo-sensor for organic guests

Fluorescent pyrrolinone-modified beta- and gamma-cyclodextrins (beta-1 and gamma-1, respectively) have been synthesized as a fluorescent chemo-sensor for organic compounds such as terpenoids and bile acids. The host compounds show a pure monomer fluorescence around 472 nm, the intensity of which dec reased when 1-adamantanecarboxylic acid, p-aminobenzoic acid, benzoic acid, phthalic acid or cyclohexanecarboxylic acid were used as a guest in an aqu eous solution of pH 5.90. On the other hand, in Menzel buffer solution of p H 9.09, the fluorescent intensity is increased by accommodation of these gu est molecules. The increase was seen with other guests such as terpenoids, amino compounds and sodium bile acid salts in a Menzel buffer solution. The extent of fluorescence variation with a guest is employed to display the c hemo-sensor ability of these hosts. The sensing parameter (Delta I/I-0) was used to show the sensing ability of those hosts. Hosts beta-1 and gamma-1 exhibit higher sensing ability for amines in a host solution of pH 5.90 tha n those in a host solution of Menzel buffer. It is probably caused by some hydrogen bonding between the carboxylic anion of the hosts and quaternary a mmonium type guests.