Synthesis and characterization of mixed-ligand ruthenium(III) complexes with oxalate and acetylacetonate ions

Abstract

Two mononuclear mixed-ligand ruthenium(III) complexes with oxalate dianion (ox 2−) and acetylacetonate ion (2,4-pentanedionate, acac −), K 2[Ru(ox) 2(acac)] ( 1) and K[Ru(ox)(acac) 2] ( 2), were prepared as a candidate for a building block. In fact, reaction of complex 2 with manganese(II) sulfate gave a heterometallic tetranuclear complex, TBA[Mn II{(μ-ox)Ru III(acac) 2} 3] ( 5) in the presence of tetrabutylammonium (TBA) bromide. The 1H NMR, UV–Vis, selected IR and FAB mass spectral data of these complexes are presented. Both mixed-ligand ruthenium(III) complexes gave a Nernstian one-electron reduction step in 0.1 mol dm −3 Na 2SO 4 aqueous solution on a mercury electrode at 25 °C. Comparison of observed reversible half-wave potentials with calculated values for a series of [Ru(ox) n (acac) 3 − n ] n− ( n=0–3) complexes by using Lever’s ligand electrochemical parameters is presented.