Three New Cd/Co/Mn‐MOFs Based on Various Metal Clusters/Metal‐Oxygen Chains for Highly Sensitive Fluorescent Sensing and Magnetic Properties

ABSTRACT Three new high‐dimensional MOFs, {[Cd 3 (L) 2 (H 2 O) 4 ]·5.5H 2 O} n ( 1 ), {[Co 2 (L)(H 2 O) 2 (OH)]·(CH 3 CN)} n ( 2 ), {[Mn(H 2 L) 2 ]} n ( 3 ) were constructed using Cd(II)/Co(II)/Mn(II) metal ions and pyridine tricarboxylate ligand 3‐(3,5‐dicarboxyphenyl)‐4‐carboxypyridine (H 3 L) under solvothermal conditions. Based on the diversity of ligand coordination patterns, the complexes show unique structures and properties. Complexes 1 – 2 are new three‐dimensional frameworks based on diverse dinuclear/tetranuclear metal clusters, respectively. Complex 1 contains a one‐dimensional cylindrical channel in its structure, which has good thermal stability. It not only has excellent solid‐state fluorescence properties at room temperature, but also can highly sensitively identify the Cr 2 O 7 2− , CrO 4 2− , and Fe 3+ in aqueous solutions with low detection limits (5.9 × 10 −4 M, 9.9 × 10 −4 M and 3.7 × 10 −4 M). In addition, the fluorescence quenching mechanism of specific ions in aqueous solution was discussed in depth. Complex 3 is a two‐dimensional layered structure with a unique Mn‐O metal oxygen chains. At the same time, the magnetic studies of complexes 2–3 confirmed the existence of antiferromagnetic interactions between adjacent metal ions within the framework.