Highly Selective Sensing of Cd(II) Ion by Hexanuclear Functionalized Zn(II) Cluster

The organic ligand 1,10-phenanthroline-2,9-dicarboxylic acid (H2L) was used to react with ZnSO4·7H2O at 140 °C for two days to obtain the complex [Zn6(L)6(H2SO4)]·3CH3CN·Et3N (1). The structure of complex is confirmed by X-ray crystallography, TG and PXRD. The structure suggested that six ligands chelated with six Zn2+ ions. Every five-coordinated Zn(II) ion is surrounded by two N atoms and three O atoms (one sulfate radical or three ligands) with the N2O3 coordination environment. Each Zn(II) ion in the structure of complex 1 binds only one L2− ligand. The metal center Zn2 and Zn3 are bridged by SO42−. The photoluminescence of complex 1 is obvious. Moreover, in the presence of Cd2+ ions, the complex exhibits an efficient recognition ability, and it realizes the recognition of toxic metal ions.