NEW RUTHENIUM(II) COMPLEXES OF ALPHA,ALPHA'-DIIMINES - SYNTHESIS, ELECTROCHEMICAL AND OPTICAL SPECTRAL PROPERTIES OF MONONUCLEAR COMPLEXES CONTAINING ARYL(2-PYRIDYLMETHYLENE)AMINE AND 2,2'-BIPYRIDINE LIGANDS

The tris-chelated complexes, [RuL(n)(bipy)3-n] [ClO4]2.H2O [L = aryl(2 -pyridylmethylene)amine, bipy = 2,2'-bipyridine, n = 0-3]. have been p repared based on a direct and general route. For [RuL3]2+, the geometr y has been assessed by H-1 NMR spectroscopy. All the complexes show me tal-to-ligand charge transfer (m.l.c.t.) transitions in the visible ra nge at ca. 475 nm. Preliminary results of emission spectra are also de scribed briefly. The metal oxidation as well as ligand reductions for the complexes have been studied electrochemically in acetonitrile usin g different working electrodes. It has been shown, for the mixed L-bip y complexes, that the reductions of co-ordinated L occur at comparativ ely lower negative potentials. The correlation between the electrochem ical properties and nu(c.t) (absorption) is discussed.