Highly Selective and Sensitive Detection of PO43– Ions in Aqueous Solution by a Luminescent Terbium Metal–Organic Framework

Abstract

A luminescent terbium metal–organic framework [Tb(HPIA^–)(PIA^2–)(H₂O)₂] (Tb-MOF), synthesized by a lanthanide metal ion (Tb³⁺) and nitric heterocyclic carboxylic acid ligands H₂PIA (H₂PIA = 5-(1H-pyrazol-3-yl)isophthalic-acid), was structurally characterized as a three-dimensional skeleton structure in which layered coordination frameworks are connected by hydrogen bonds. Based on the antenna effect, Tb-MOF can emit bright green fluorescence under 254 nm excitation, and the fluorescence emission presents excellent durability in aqueous solutions among a wide pH range. Moreover, the structure of Tb-MOF also possesses outstanding thermal stabilities. In some ways, PO₄^3– and its derivatives are thought to be a kind of pollutant ion causing series environmental and health problems. The as-synthesized Tb-MOF exhibits prominent selectivity and remarkable sensitivity for detecting PO₄^3– as an easy-to-use fluorescent probe with low detection limit, fast response, and wide detection range. Therefore, Tb-MOF has significant applications in the fields of human health and environmental monitoring.