Coordination Frameworks Containing Magnetic Single Chain of Imidazoledicarboxylate-Bridged Cobalt(II)/Nickel(II): Syntheses, Structures, and Magnetic Properties

Five new magnetic coordination frameworks with formulas of {[Co2(HL)2(H2O)4]·4H2O}n (1), {[Ni2(HL)2(H2O)4]·4H2O}n (2), [Co(HL)(bpy)]n (3), [Co(HL)(pbim)]n (4), and [Ni(HL)(pbim)]n (5) [H3L = 2-(5-bromo-pyridin-3-yl)-1H-imidazole-4,5-dicarboxylic acid, bpy = 4,4′-bipyridine, and pbim = 1,1′-(5-methyl-1,3-phenylene)bis(1H-imidazole)] have been synthesized and structurally characterized by elemental, thermogravimetric, and X-ray diffraction analyses. In all compounds, the doubly deprotonated (HL)2– ligands adopt the same μ-kN,O:kN′,O′ coordination mode, showing very interesting coordination orientation in the construction of those coordination polymers. Complexes 1 and 2 feature (HL)2–-bridged linear chain structures. Complex 3 is a 2D network with (4,4) grids built up from the (HL)2–-bridged linear chains observed in 1 being further linked by rod-like bpy bridges replacing the coordination of water molecules. Those almost or completely linear chains formed by the bis-N,O-chelation of the imidazoledicarboxyl...