Ratiometric and Selective Fluorescent Sensor for CuIIBased on Internal Charge Transfer (ICT)

Abstract

A Cu^II-sensing, ratiometric, and selective fluorescent sensor 1, N-butyl-4,5-di[(pyridin-2-ylmethyl)amino]-1,8-naphthalimide, was designed and synthesized on the basis of the mechanism of internal charge transfer (ICT). In aqueous ethanol solutions of 1, the presence of Cu^II induces the formation of a 1:1 metal−ligand complex, which exhibits a strong, increasing fluorescent emission centered at 475 nm at the expense of the fluorescent emission of 1 centered at 525 nm.