Synthesis, characterization and reversible binding of dioxygen and carbon monoxide in ruthenium(III) schiff-base complexes. Effect of equatorial substitution on the O 2 and Co affinities

Abstract

Synthesis of a series of ruthenium(III) Schiff-base complexes of the type K[RuLX 2] (where L = dibasic Schiff bases derived from methoxy, chloro substituted salicyl-aldehyde with o-phenylenediamine, propylenediamine and ethylenediamine, X = chloride) have been accomplished. The complexes were characterized by physicochemical methods. The formation of Ru IV superoxo complexes was confirmed electrochemically and by IR spectroscopy. The reversible binding of oxygen and carbon monoxide to these complexes were carried out in DMF at 10, 25 and 40°C. The substituents on salicylaldehyde increase the value of equilibrium constants K O 2 and K CO for the oxygenation and carbonylation reactions. The thermodynamic parameters Δ H 0, Δ G 0 and Δ S 0 for oxygenation and carbonylation were evaluated.