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

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 (6(12).8(3))(6(3))(2). Polymer 2 showed a 4-c sql network with a point symbol of (4(4).6(2)), which was further linked to a 3D framework by O-H center dot center dot center dot 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 mu M, respectively. Moreover, 1 showed that Fe3+, CrO42-, and Cr2O72- could be detected by fluorescence quenching in the temperature range of 10-70 degrees C.