A terbium(iii) lanthanide–organic framework as a platform for a recyclable multi-responsive luminescent sensor

Abstract

A terbium(III) lanthanide–organic framework (534-MOF-Tb) with a green-emission signal was successfully obtained by the solvothermal reaction of Tb³⁺ ions with the organic ligand H₃TBOT (2,4,6-tris[1-(3-carboxylphenoxy)ylmethyl]mesitylene). 534-MOF-Tb contains microporous quadrangle channels with accessible Lewis-base sites and coordinated water molecules, which are feasible to anchor and recognise multifarious analytes. It can serve as a recyclable multi-responsive sensing material for detecting Fe³⁺, MnO₄⁻, Cr₂O₇²⁻, and p-nitrotoluene (4-NT). Significantly, this is the first reported MOF-based sensor for detecting explosive 4-NT. Moreover, the mechanism of the selective luminescence quenching response for Fe³⁺, MnO₄⁻, Cr₂O₇²⁻ or 4-NT can be mainly explained in terms of the competition between the absorption of the light source energy and the electronic interaction between the analyte and the TBOT ligand.