Luminescent Zn(II)/Cd(II) coordination polymers based on 1-(tetrazol-5-H)-3,5-bis(1-triazole)benzene for sensing Fe3+, Cr2O72−, and CrO42− in water

Abstract Two new Zn(II)/Cd(II) coordination polymers based on the 1-(tetrazol-5-H)-3,5-bis(1-triazole)benzene (HL) ligand, [Zn(L)2]n (1) and [Cd (L)2(H2O)2]n (2), were successfully synthesised by the solvothermal method. Polymer 1 possessed a 3D 2-fold interpenetrated 3,6-c pyr topology with a Schlafli symbol of (612·83)(63)2. Polymer 2 showed a 4-c sql network with a point symbol of (44·62), which was further linked to a 3D framework by O-H⋯N hydrogen bonds. The fluorescent responses of 1 towards Fe3+, CrO42−, and Cr2O72− was investigated in aqueous solutions, and the detection limits of polymer 1 for Fe3+, CrO42−, and Cr2O72− were 2.24, 2.56, and 0.67 ​μM, respectively. Moreover, 1 showed that Fe3+, CrO42−, and Cr2O72− could be detected by fluorescence quenching in the temperature range of 10–70 ​°C.