Syntheses, structures, and properties of three mixed-ligand complexes based on 3,6-bis(imidazole-1-yl)pyridazine

Abstract

Three new coordination polymers [Co(L)(1,2,4,5-BTC)0.5(H2O)]n (1), {[Ni(L)(1,2-BDC)(H2O)3]·H2O}n (2) and {[Zn3(L)2(1,3,5-BTC)2(H2O)2]·3H2O}n (3) [L = 3,6-bis(imidazole-1-yl)pyridazine, H4BTC = 1,2,4,5-Benzenetetracarboxylic acid, H2BDC = 1,2-Benzenedicarboxylic acid, H3BTC = 1,3,5-Benzenetricarboxylic acid] were synthesized based on a rigid ligand L and different aromatic carboxylic acid ligands under solvothermal conditions. The structures of the complexes 1–3 were determined by single crystal X-ray diffraction and further characterized by elemental analyses, IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). In addition, UV–vis diffuse-reflectance spectra demonstrate wide band gaps. The structural analysis reveals that complex 1 features a two-dimensional (2D) layer structure with a 6-connected sql topological net. Complex 2 shows a one-dimensional (1D) zigzag chain, while complex 3 displays a three-dimensional (3D) coordination network which exhibits an intriguing (5,5,6)-connected novel topological net with the point symbol of {32·42·53·63}2{32·44·54·63·72}. Moreover, the luminescence property and lifetimes of complex 3 has been measured at room temperature. Furthermore, in the complex-catalyzed homocoupling reaction of 4-substituted aryl iodides, the catalytic activities of complexes 1–3 have also been studied and discussed.