A binuclear Zn(ii)–Zn(ii) complex from a 2-hydroxybenzohydrazide-derived Schiff base for selective detection of pyrophosphate

Abstract

A hydroxybenzohydrazide-based Schiff base ligand was conveniently synthesized. Upon addition of Zn²⁺ cations, the ligand exhibited a high tendency to form a binuclear structure with a 2 : 2 ligand-to-zinc ratio, which was accompanied by a large fluorescence turn-on (λ_em = 507 nm, ϕ_fl ≈ 0.28). The reactivity of the zinc complex was examined using different phosphate anions, which reveals a higher response to acid pyrophosphate anions. Detailed spectroscopic studies show that the pyrophosphate response is based on the ligand displacement mechanism.