Two series of Ln-MOFs by solvent induced self-assembly demonstrating the rapid selective sensing of Mg 2+ and Fe 3+ cations

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 49; no. 43; pp. 15473 - 15480
• Main Authors: Wang, Xiaokang, Wang, Yutong, Wang, Xia, Lu, Kebin, Jiang, Weifeng, Cui, Pei-Pei, Hao, Hongguo, Dai, Fangna
• Format: Journal Article
• Language: English
• Published: 10.11.2020
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/D0DT03264F

Two series of lanthanide-based metal–organic frameworks, namely {[Ln(BIPA-TC) 0.5 (DMA) 2 (NO 3 )]·DMA·H 2 O} n ( 1-Ln , Ln = Eu, Dy, Sm, Nd) and {[Ln 2 (BIPA-TC) 1.5 (DMA) 3 (H 2 O) 2 ]·2DMA·2H 2 O} n ( 2-Ln , Ln = Eu, Dy, Sm, Nd), were successfully constructed via a solvent regulation strategy based on a π-electron rich tetra-carboxylate ligand (H 4 BIPA-TC). 1-Ln shows a 4-connected lvt topology with the point symbol of {4 2 ·8 4 }, but 2-Ln displays a new 4,4,6-connected wxk1 topology with the point symbol of {4 3 ·8 3 } 4 {4 6 ·6 6 ·8 3 } 2 {8 6 }. The solid-state luminescence property and the microporous nature of Eu-MOFs ( 1-Eu and 2-Eu ) indicate that they can potentially be used as luminescent sensors. Fluorescence measurements indicate that Fe 3+ exhibits the quenching effect for 1-Eu with the quenching efficiency of 93.1%. 2-Eu is the first MOF sensor for Mg 2+ with the lowest detection limit of 1.53 × 10 −10 mol L −1 and displays good recyclable capability. Simultaneously, in the presence of other metal ions (Ca 2+ , Mn 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , Cd 2+ , Pd 2+ , Al 3+ , Cr 3+ and Fe 3+ ), 2-Eu can maintain the selective sensing of Mg 2+ , indicating its potential for Mg 2+ turn-on sensing.