Dual-channel recognition of Al3+ and Cu2+ ions using a chiral pyrene-based fluorescent sensor

Abstract

A chiral cation sensor comprising two pyrene rings and a diethylene glycol linker has been developed and utilized to detect Al³⁺ and Cu²⁺ ions based on differences in circular dichroism spectra. Remarkably, this sensor afforded the recognition of Al³⁺ and Cu²⁺ ions based on distinct differences in fluorescence spectra. The detection of Al³⁺ ions was achieved based on a typical excimer-to-monomer switching mechanism, whereas the oxidative dimerization of pyrenyl groups was proven to be the origin of the Cu²⁺-responsive switch in fluorescence spectrum. The Cu²⁺ cation-triggered formation of bipyrene structures, a process that has so far been overlooked in the development of pyrene-based sensors, holds promise for the generation of dual-responsive fluorescent sensors that afford the detection of two different analytes.