Catalytic potential of new mononuclear Cr(III)-Schiff base complexes for selective oxidation of benzyl alcohol by H2O2

In the present contribution, some novel Cr(III) complexes were  synthesized from tri- and tetra-dentate imine ligands derived from 3-Ethoxysalicylaldehyde or  2-hydroxynaphthaldehyde with 2-aminophenol or o-phenylenediamine. All the prepared ligands were authenticated by IR, ¹H, ¹³C NMR spectra and CHN analysis. Interaction of the synthesized ligands with chromium nitrate produced three novel Cr(III) complexes. The structure of the prepared Cr(III) complexes was elucidated by elemental analysis, infrared, ultraviolet-visible spectra, thermogravimetric analysis, molar conductance as well as magnetic moment measurements. Furthermore, the catalytic potentials of the prepared Cr(III) complexes have been tested within the oxidation of benzyl alcohol using an environmental friendly terminal oxidant, i.e. H₂O₂.  In addition to, effect of various parameters, e.g. solvents, temperature and amount of catalyst was investigated. The obtained results indicated that the most favored solvent is acetonitrile at optimal temperature 80 °C after 4 hours. The mechanistic pathway of the catalytic oxidation was tentatively described and discussed.