Synthesis, Crystal Structure and Electrochemical Studies of Two Novel Zn(II) Complexes of Phthalic Acid and Imidazole Derivatives

Two novel coordination polymers [Zn(pa)(vim)(2)](n) (1) and [Zn(pa)(eim)(2)](n) (2) (pa=phthalic acid dianion, vim=1-vinyl-1H-imidazole, eim=1-ethyl-1H-imidazole) have been synthesized and their structures characterized by X-ray single crystal diffractometry and elemental analysis. Both of the complexes consist of [Zn(L)21 (L=vim for 1; eim for 2) entities linked into polymeric zigzag chains along the crystallographic c-axis by bridging phthalate anions in the mu(2)-1,2 coordination mode. The coordination around each Zn(II) atom is tetrahedral. There are only van der Waals interactions between the chains in 1, while the three-dimensional network in 2 is assembled by C-H center dot center dot center dot O contacts. The electrochemical studies reveal that redoxes of Zn(2+)/Zn in complexes 1 and 2 are irreversible processes.