Multiresponsive Luminescent Sensitivities of a 3D Cd-CP with Visual Turn-on and Ratiometric Sensing toward Al and Cr as Well as Turn-off Sensing toward Fe.

By using the reduced Schiff base tricarboxylate ligand Hcip, one novel 3D Cd-based coordination polymer () with the formula [Cd(Hcip)(bpea)(HO)] (Hcip = 5-(3-carboxybenzylamino)isophthalic acid, bpea = 1,2-bis(4-pyridyl)ethane) has been solvothermally synthesized. The prepared possesses a 4-connected CdSO net based on dinuclear {Cd} units. Luminescence measurements revealed that the complex exhibited ratiometric turn-on luminescence responses toward Al and Cr with a significant color change, which could be easily distinguished by the naked eye under ultraviolet light. can also respond to Fe through a turn-off mechanism. Interestingly, the luminescence quenched by Fe@ can be recovered and increased significantly by adding some competitive Al, while Cr can only marginally increase the luminescence intensity of Fe@. Moreover, the detection of the three aforementioned metal ions can be realized by using -coated test papers, extending the potential application regions of the reported material to point-of-care tests and environmental field studies.