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

• Seven complexes with 1D, 2D and 3D structures have been obtained.
• Complex 7 shows a 3D 4-fold interpenetrated dia network.
• The N/S-containing dicarboxylates have great effect on the structures of 1–7.
• Complexes 1–7 show photocatalytic and luminescent activities.

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.

Seven metal–organic coordination polymers have been hydrothermally synthesized using a semi-rigid 1,4-bis(imidazol-1-ylmethyl)benzene (L) as the main ligand and two N/S-containing dicarboxylates as the auxiliary ligands. The effects of the central metals and dicarboxylates on the structures of coordination polymers have been discussed.Figure optionsDownload as PowerPoint slide