Synthesis, characterization and properties of heteronuclear ruthenium(III) complexes of N,N'-o-bis[1-p-diphenylmethane-2-(arylamine)-1-ethiliden]-phenylenediamine quadridentate ligands

In this study, we synthesized the amine compounds (1-p-diphenylmethane-2-hydroxyimino-2-(1-arylamino)-1-ethanones) [HL1 (2) and HL2 (9)] as the starting material, and then we prepared the quadridentate tetraaza Schiff base ligands [H2L3 (3) and H2L4 (10)] from the reactions of the amine compounds with 1,2-phenylenediamine. A new series of mononuclear Ru(III) (4), (11), heterodinuclear Ru(III)-Mn(II) (8), (15), Ru(III)-Ni(II) (7), (14), Ru(III)-Cu(II) (5), (12) and heterotrinuclear Ru(III)-Cu(II)-Ru(III) (6), (13) complexes have been synthesized using the quadridentate oxime-imine ligands, 1,10-phenanthroline monohydrate, ruthenium(III) and a second metal salts. The complexes were characterized by elemental analysis, molar conductivity, IR, ESR, ICP-OES, magnetic moment measurements and thermal analyses studies. The free ligands were also characterized by H-1-NMR spectra. The quadridentate tetraaza ligands coordinates with Ru(III) through its nitrogen donors in the equatorial position with loss of one of the oxime protons and concomitant formation of an intra-molecular hydrogen bond. Stoichiometric and spectral results of the metal complexes indicated that the metal: ligand ratios of the mononuclear complexes were found to be 1:1 while ratios 2:1 in the dinuclear complexes and 3:2 in the trinuclear complexes.