A pyrene-appended spiropyran for selective photo-switchable binding of Zn(II): UV-visible and fluorescence spectroscopy studies of binding and non-covalent attachment to graphene, graphene oxide and carbon nanotubes

Abstract

Synthesis of photo-switchable, Zn2+ sensitive hybrid materials was achieved by facile non-covalent functionalization of graphene, graphene oxide and carbon nanotubes with a pyrene-appended spiropyran. Solution phase binding studies, using UV–visible and fluorescence spectroscopy, indicated that the pyrene-spiropyran dyad was highly selective for Zn2+ over a range of potentially competitive cations and that binding occurred with 1:1 stoichiometry and a binding constant of K=1.4×104 mol−1 dm3 at 295 K. Zn2+ binding was promoted by UV irradiation or in darkness and reversed upon irradiation with visible light.