The reaction between NiCl2·6H2O and pyridin-2-on in molar ratio 1:3 in acetonitrile was carried out for one hour at 60ºC and then two days at room temperature. The resulting suspension was filtered. Beautiful crystals of a new dinuclear compounds were isolated from the resulting filtrate or precipitate dissolved in acetonitrile, if crystallization took place in a closed system. The structure of this complex [Ni2(C5H5NO)5Cl4]·2CH3CN, was determined by X-ray structural analysis. The X-ray powder analysis and CHN analysis revealed that the precipitate obtained in the reaction was a mixture of [Ni2(C5H5NO)5Cl4].2CH3CN and [Ni(C5H5NO)Cl2(H2O)2]2.2C5H5NO. We can conclude that in the presence of moisture, [Ni2(C5H5NO)5Cl4].2CH3CN converted into [Ni(C5H5NO)Cl2(H2O)2]2.2C5H5NO.
In a dinuclear molecule [Ni2(C5H5NO)5Cl4], three bridging pyridin-2-on molecules connect two nickel ions. Four molecules of pyridin-2-on and two chloride ions in cis position are coordinated to a central nickel ion. The ligands are in the corners of a distorted octahedron.