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