Binuclear ruthenium(III) Schiff base complexes bearing N4O4 donors and their catalytic oxidation of alcohols

An interesting series of binuclear ruthenium(III) Schiff base complexes bearing bis-salophen/bis-naphophen units of the general composition [(EPh3)(X)Ru-L-Ru(X)(EPh3)] (where E = P or As; X = Cl or Br; L = binucleating dianionic tetradentate ligands) have been synthesized and characterized by analytical (elemental analysis, magnetic susceptibility measurements), spectral (FT-IR, UV–vis and EPR) and electrochemical methods. These ruthenium(III) complexes have two N2O2 metal binding sites, which are linked to each other with a biphenyl bridge and acts as potential catalyst for oxidation of wide range of primary and secondary alcohols to corresponding aldehydes or ketones with moderate to high conversion in the presence of N-methylmorpholine-N-oxide (NMO). The formation of high-valent RuV = O species as a catalytic active intermediate is proposed for the catalytic processes.

Graphical abstractA new class of binuclear ruthenium(III) Schiff base complexes containing potential N4O4 donors have been synthesized, characterized and employed as catalyst for the oxidation of a number of primary and secondary alcohols in the presence of N-methylmorpholine-N-oxide.Figure optionsDownload full-size imageDownload as PowerPoint slide