Synthesis and Characterization of 3-(Aryl azo)-4-hydroxy-1,2-naphthoquinone Ruthenium(III) Complexes as Catalysts for Benzyl Alcohol Oxidation

Abstract

The syntheses and characterization of 3-(p-substituted phenyl azo)-4-hydroxy-l,2-naphthoquinones ligands (L1-3) and their Ru(III) complexes (Ru1-3) are carried out. The characterization was ascertained by elemental analysis, thermal analysis, spectroscopic analyses (FT-IR, 1H NMR, UV-vis and Mass), magnetic, molar conductance, molecular calculations and electrochemical techniques. The green catalytic conversion of some benzyl alcohols to benzoic acid derivatives was successfully achieved by using these complexes in an aqueous KOH with K2S2O8 as co-oxidant; with high yields by using Ru3 complex. Computational modeling was carried out to predict the structural geometry, magnetic characters and the electron donor/acceptor functions of the prepared complexes along with experimental results. The mechanism of benzyl alcohol oxidation was developed through an orange ruthenate-persulfate reagent. The oxidation capacities of the ruthenium complexes were better than the other catalysts reported. The present results are useful to oxidize benzyl alcohols at an industrial scale with a good economy.