A selective fluorescent sensor for Zn2+ based on aggregation-induced emission (AIE) activity and metal chelating ability of bis(2-pyridyl)diphenylethylene

Polypyridyl ethylenes have been prepared as heterocyclic analogues of tetraphenylethylene. In addition to conventional AIE effects, a derivative possessing a 1,1-bis(2-pyridyl)ethylene fragment displays Zn(2+)-selective enhanced fluorescence in aqueous solution, in contrast to the behavior of isomeric bis(3- and 4-pyridyl)ethylenes. The Zn(2+)-sensing capability of this material is attributed to formation of chelated Zn(2+)-bis(pyridyl) complexes and is supported by the X-ray crystal structure of a bis(2-pyridyl)ethylene-Zn(OAc)2 complex.