Pyridine-2,5 Acid Complexes of Nickel(II) with 2,2́-Bipyridine and 1,10-Phenanthroline Coligands; Syntheses, Crystal Structures, Spectroscopic and Thermal Studies

Abstract

Two pyridine-2,5-dicarboxylic acid (pydcH<inf>2</inf>) complexes of nickel(II) with 2,2́-bipyridine and 1,10-phenanthroline were synthesized and characterized by elemental, spectroscopic, thermal analysis, magnetic measurements and single crystal X-ray diffraction techniques. Both [Ni(pydc)(bipy)<inf>2</inf>]•7H<inf>2</inf>O and [Ni(pydc)(phen) <inf>2</inf>]•6.5H<inf>2</inf>O crystallize in the monoclinic system and P2<inf>1</inf>/c space group. The Ni(II) ions are coordinated by two bidentate bipy or phen ligands and one pydc dianion in a distorted octahedral geometry. The pydc ligand is coordinated through the pyridine nitrogen atom and oxygen atom of carboxyl group as a bidentate ligand. Both carboxylate groups of pydc are deprotonated but only the 2-carboxylate is coordinated to the metal. Thermal decompositions of the complexes have been studied over the range 30-600 °C on heating in a static air atmosphere. © 2009 Springer Science+Business Media B.V.