CHELATION-ENHANCED FLUORESCENCE OF ANTHRYLAZAMACROCYCLE CONJUGATE PROBES IN AQUEOUS-SOLUTION

In this paper, we report the synthesis of several anthrylazamacrocycles designed to provide chelation-enhanced fluorescence on complexation of nonquenching metal ions [e.g., Zn(II) and Cd(II)] in totally aqueous solution. The N3, N4, N5, and N6 derivatives are water-soluble compounds whose fluorescence is enhanced by addition of Zn(II) and Cd(II) and quenched by addition of Cu(II) and Hg(II). While the background fluorescence of anthrylazamacrocycles is higher in water than in aprotic solvents, large (20-190-fold) overall fluorescence changes are still obtained on complexation. The titration of these metal ions is unaffected at pH 12 by even very high (1 M) concentrations of nonbinding metals such as Na+. pH-fluorescence profiles for the anthrylazamacrocycles support intramolecular amine fluorescence quenching at basic pH. These results suggest that the large body of literature on the synthesis of selective azamacrocycle binders can be used in a direct way for the design of conjugate fluorescent probes for those metals. © 1990, American Chemical Society. All rights reserved.