A series of flexible bis(imidazole)-based coordination polymers tuned by central metal ions and dicarboxylates: Diverse structures and properties

Seven new coordination polymers, namely, [Ni(L)1.5(2-CMSN)(H2O)]·2H2O 1, [Co2(L)2(2-CMSN)2(H2O)]·H2O 2, [Cd(L)(2-CMSN)(H2O)] 3 [Zn(L)(2-CMSN)]·2H2O 4, [Cd(ADTZ)(H2O)] 5, [Cd(L)(ADTZ)(H2O)] 6, and [Zn(L)(ADTZ)]·H2O 7 [where 2-H2CMSN = 2-carboxymethylsulfanyl nicotinic acid, H2ADTZ = 2,5-(s-acetic acid) dimercapto-1,3,4-thiadiazole, L = 1,4-bis(imidazol-1-ylmethyl)benzene] have been synthesized under hydrothermal conditions. The complexes were structurally characterized by single crystal X-ray diffraction analyses, infrared spectroscopy (IR), elemental analyses, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Complex 1 features a 1D ladder-like double chain. Complexes 2 and 3 exhibit the similar 2D networks based on six-nuclear metallic rings. Complex 4 is a 2D sheet. Complex 5 exhibits a 3D (4,6)-connected (43·53)(45·53·67) topology. Complex 6 shows a 2D undulated network with the Schläfli symbol of (3·52)(32·53·64·7). Complex 7 is a 3D 4-fold interpenetrated dia network. Structural comparison of these polymers suggests that different central metals and dicarboxylates play important roles in the construction of 1–7. The luminescent properties of complexes 3, 4, 6, 7 and the electrochemical properties of complexes 1, 2 have been investigated. Furthermore, the complexes 2–4, 6 and 7 exhibit photocatalytic activities for dye methylene blue degradation under UV light and show good stability toward photocatalysis.