Multi-responsive luminescent sensors of two water-stable polynuclear Cd organic frameworks: Synthesis, structures and sensing of tetracycline, Cr2O72− and Fe3+ ions in water.

• Two novel polynuclear Cd-MOFs have been successfully synthesized and characterized. • 1 shows a rare 3D 2-nodal (5,10)-c fit network based on tetranuclear [Cd 4 (µ 3 -O) 4 (COO) 10 ]2− unit. • 2 displays an interesting 2D → 3D interdigitating and penetrating structure unique topological framework. • 1 – 2 can serve as excellent multi-responsive luminescent sensors for TC, Cr 2 O 7 2− and Fe3+ ions. • The 2 -coated fluorescent test papers can be used to detect TC, Cr 2 O 7 2− or Fe3+ ions in water system. Assembled from O-containing pentacarboxylate acid ligand (H 5 L), two new water-stable Cd organic frameworks (Cd-OFs), namely {[Cd 4 L 2 ]·1,4-bmib} n (1) and [Cd 4 L 2 (1,4-bimb) 3 ] n (2) have been solvothermally synthesized and further characterized. Cd-OF 1 possesses a rare 2-nodal (5,10)-c fit topological 3D network based on tetranuclear [Cd 4 (µ 3 -O) 4 (COO) 10 ]2− unit. Cd-OF 2 displays an interesting 2D → 3D interdigitating and penetrating structure with a unique 3-nodal (3,3,5)-c topological framework. The luminescence performance of Cd-OFs 1 – 2 has been investigated based on their high thermal and good chemical stability. These results reveal that 1 – 2 can serve as multi-responsive luminescent sensors for tetracycline (TC), Cr 2 O 7 2− and Fe3+ ions with excellent selectivity and highly sensitive sensing ability. Interestingly, the Cd-OF 2 -coated fluorescent test papers can be used to detect TC, Cr 2 O 7 2− and Fe3+ ions in water system, and thus may have promising application prospect. [ABSTRACT FROM AUTHOR]