Syntheses,Structures and Properties of Three Transition Metal Coordination Polymers Based on Semi-rigid 3-Pyridylnicotinamide and S/N-Containing Dicarboxylate Mixed Ligands

Three new coordination complexes,Co(L)(ADTZ)]·H₂O(1),Cd(L)(ADTZ)]·H₂O(2) andZn(L)(ADTZ)]·H₂O(3)L=3-pyridylnicotinamide, H₂ADTZ=2,5-(s-acetic acid)dimercapto-1,3,4-thiadiazole], were synthesized under hydrothermal conditions. These complexes were structurally characterized by single-crystal X-ray diffraction analysis and further characterized by infrared spectroscopy(IR), powder X-ray diffraction (PXRD) and thermogravimetric analysis(TGA). Complexes 1-3 exhibit the similar 2D double-layer networks based on 1DM-L]_n zigzag chains and 1DM-ADTZ]_2n double-chains with different distances between metal ions and with various conformations of ADTZ anions. In complexes 1 and 3, the 2D sheets are extended into a 3D supramolecular frameworks by hydrogen bonding interactions. The subtle effects of the central metal atoms on the structures of the title coordination polymers were discussed. The electrochemical properties of complex 1 and luminescent properties of complexes 2 and 3 were investigated. In addition, complexes 1-3 exhibit photocatalytic activity for dye methylene blue degradation under UV light and show good stability toward photocatalysis.