The binary pyrene/heptakis-(6-amino-6-deoxy)-β-cyclodextrin complex: A suitable chiral discriminator. Spectrofluorimetric study of the effect of some α-amino acids and esters on the stability of the binary complex

Abstract

The effect of some α-amino acids and their esters on the stability of the binary pyrene/heptakis-(6-amino-6-deoxy)-β-cyclodextrin (py/am-β-CD) complex has been studied by means of fluorescence spectroscopy at two pH values (8.0 and 9.0). The binary complex was generally stabilized by adding the ternary agent at pH 8.0. A more varied substrate effect is observed at pH 9.0 where am-β-CD is present in the uncharged form. The conditional constant (β2) values determined by L/D α-amino acids show that the binary complex is a suitable receptor for chiral recognition. The enantiomer selectivity values obtained, ranging from 1.2 up to 7.4, are generally higher than those reported for α-amino acids and their derivatives by modified cyclodextrins. © 2002 Elsevier Science Ltd. All rights reserved.