Zinc(II) complexes of 4,4-oxybis(benzoate) and 2-propyl-4,5-imidazoledicarboxylic acid with bipyridine

The reactions of dicarboxylic acids, such as 4,4-oxybis(benzoic acid) [H(2)oba] and 2-propyl-4,5-imidazoledicarboxylate [H(3)pimdc], under hydrothermal conditions in the presence of an appropriate zinc salt yield two mononuclear complexes, which are characterized by elemental analysis, infrared spectrum, electrochemical analysis, thermal analysis, and X-ray crystal diffraction. Complex 1, [Zn(Hoba) 2(4,4'-bpy)(2)], forms a 2-D supramolecular layer like rhombus via hydrogen bonds (O-H center dot center dot center dot N). Complex 2, [Zn(H(2)pimdc)(2)(2,2'-bpy)] center dot H2O, forms a zig-zag chain via multiple hydrogen bonds and C-H center dot center dot center dot pi interactions. The moderate hydrogen-bond interactions in 1 and 2 play an important role for structural stability. The electrochemical analyses of 1 and 2 reveal electron transfer of 1 is reversible and 2 is quasi-reversible.