Fluorescent ratioable recognition of Cu2+ in water using a pyrene-attached macrocycle/γ-cyclodextrin complex

A pyrene-functional fluoroionophore, 1 was used to construct a supramolecular 1/gamma-CD complex for Cu2+ recognition in water. In aqueous gamma-CD solution, I exhibits pyrene monomer fluorescence emission at 378 nm and 397 nm, while in the presence of Cu2+, it shows a pyrene excimer emission at 452 nm with a decrease in the monomer fluorescence due to the formation of a 1:2 metal-liganded complex. Based on the response characteristics of the supramolecular complex, a fluorescent ratiometric method was performed for the determination of Cu2+ concentration in water. With the optimum conditions described, Cu2+ in aqueous solution can be determined from 1.2 x 10(-6) to 4.5 x 10(-4) M. The Cu2+ selectivity of the complex is excellent, and the excimer fluorescence enhancements are very smaller induced by other heavy metal and transition metal ions. (C) 2004 Elsevier B.V. All rights reserved.