Syntheses, Crystal Structures and Magnetic Properties of Co(II) Coordination Polymers Based on a Rigid Imidazole Derivative

Two new Co(II)-based coordination polymers, [Co(bib)(SO4)(H2O)2]n·nH2O (1) and [Co(bib)(bptc)0.5(H2O)2]n (2) [bib = 1,4-bis (imidazol-1-yl) benzene, H4bptc = 3,3′,5,5′-biphenyltetracarboxylic acid] have been successfully synthesized under solvothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, X-ray powder diffraction and thermogravimetric analysis. The structure analysis reveals that complex 1 exhibits a novel one-dimensional double chain with μ-O atom of SO42− anion bridging the 1D [Co(bib)]∞ chain, while complex 2 shows a 2D (4, 4) net work with deprotonated H4bptc links 1D [Co(bib)]∞ chain. The organic carboxylic acid competes with inorganic acid on the architectures of Co(II) coordination polymers. Furthermore, magnetic properties of 1 and 2 are measured and show antiferromagnetic characters.