Multi-responsive luminescent sensor based on three dimensional lanthanide metal–organic framework

Abstract

A new lanthanide-based metal–organic framework (Ln-MOF), namely, [Eu(L)(H₂O)]·1.5H₂O (1) (H₃L = 3-(3,5-dicarboxylatobenzyloxy)benzoic acid), has been successfully synthesized and exhibits a fascinating three-dimensional (3D) structure with left- and right-hand helical chains, which are built from Eu³⁺ ions and three carboxylate groups. Moreover, 1A (activated product of 1) emits strong red light in the solid state at room temperature and shows good solvent stability. Observably, 1A can be used as a multi-responsive luminescent sensor for probing acetone, Fe³⁺, Cr₂O₇²⁻ and 4-nitrophenol (4-NP) in aqueous solutions with detection limits of 0.0704 vol%, 0.87 μmol L⁻¹, 1.25 μmol L⁻¹ and 0.92 μmol L⁻¹, respectively. 1A can also be regenerated at least five times for sensing Fe³⁺, Cr₂O₇²⁻ and 4-NP. In addition, 1A possesses pH-dependent luminescence response ability in a wide pH range.