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

Abstract

The reactions of dicarboxylic acids, such as 4,4-oxybis(benzoic acid) [H₂oba] and 2-propyl-4,5-imidazoledicarboxylate [H₃pimdc], 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 ··· N). Complex 2, [Zn(H₂pimdc)₂(2,2′-bpy)] · H₂O, forms a zig-zag chain via multiple hydrogen bonds and C–H ··· π 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.

Keywords:

• Electrochemical analysis
• Thermal analysis
• X-ray crystal diffraction
• Hydrogen bonds
• C–H ··· π interactions

Acknowledgments

The authors thank the National Natural Science Foundation of China (20761002), PR China, the Natural Science Foundation of Guangxi (0832080), PR China, and the Innovation Project of Guangxi University for Nationalities (gxun-chx2010083).