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

Abstract

Assembled from O-containing pentacarboxylate acid ligand (H5L), two new water-stable Cd organic frameworks (Cd-OFs), namely {[Cd4L2]·1,4-bmib}n (1) and [Cd4L2(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 [Cd4(µ3-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), Cr2O72− 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, Cr2O72− and Fe3+ ions in water system, and thus may have promising application prospect.