Synthesis and characterisation of some Ru(II) complexes of 2-carbamoylpyridine derivatives

Abstract

p-Substituted N-phenyl derivatives of 2-carbamoylpyridine (L) have been prepared by the reaction of pyridine-2-carboxylic acid with p-substituted aniline. Five complexes of the type [Ru(L)(DMSO) 2Cl 2] have been synthesized by the reaction of [Ru(DMSO) 4Cl 2] with L. The amide ligands have been characterized by elemental analysis, infra red and 1H NMR spectral studies. The complexes are diamagnetic and show intense absorptions due to metal to ligand charge transfer (MLCT) transitions in the UV–visible spectra. The IR spectra of the complexes show that the amide ligands coordinate to the ruthenium (II) ion as a bidentate ligand coordinating from pyridyl nitrogen and from the carbonyl oxygen of the amide group. The complexes undergo a reversible ruthenium (II)–ruthenium (III) oxidation near 0.55 V in acetonitrile solution. The ruthenium (II)–ruthenium (III) oxidation potentials of the complexes are found to be sensitive to the nature of the substituent on the ligand.