The potential for constructing metal complexes that bridge between classical coordination and supramolecular chemistry seems unlimited [1]. The approach has applied in the preparation of supramolecular systems is synthesis of self-assembled supramolecular proton transfer compounds and the complexation with metal ions [2]. In this report, the complexation of zinc(II) with proton transfer compound including pyridine-2,6-dicarboxylic acid and phenyl hydrazine were investigated. For preparation of proton transfer compound, to an aqueous solution of pyridine-2,6-dicarboxylic acid, pydcH2, (10 mmol), was added a solution of phenyl hydrazine, phenhz, (20 mmol). Yield: 93%, mp=218°C. Then, a solution of Zn(NO3)2·4H2O (0.5 mmol) was added to a stirring solution of proton transfer compound phenyl hydrazinum, (pydc)(phenhzH)2, (1 mmol). Colorless crystals were obtained after 10 days. mp= 308°C. In the molecular structure of complex, [Zn(pydcH)2]·2H2O, the metal center lies in a pseudo-octahedral environment with four oxygen and two pyridine nitrogen atoms of two (pydcH)– ligands. There are also two uncoordinated water molecules in the structure. Investigation of the packing diagram confirms that the structure is stabilized by a complicated network of hydrogen bonding. Therefore, hydrogen bonding plays an important role in the construction of three dimensional framework. The uncoordinated water molecules increase the number of hydrogen bonds in the whole crystal lattice. Keywords: Zinc(II); Pyridine-2,6-dicarboxylic acid; Phenyl hydrazine; Crystal structure
