Synthesis, structural characterization, and benzyl alcohol oxidation activity of mononuclear manganese(II) complex with 2,2′-bipyridine: [Mn(bipy)2(ClO4)2]

A manganese(II) complex of 2,2'-bipyridine (bipy) was synthesized and characterized by X-ray diffraction, IR, and UV-vis spectroscopy. The activity of the complex was tested for oxidation of benzyl alcohols using t-BuOOH as an oxidant in organic solvents and in an organic/water biphasic system (hexane/H2O, toluene/H2O). The effect of solvent, temperature, oxidant, and some additives (KBr, N(C4H9) Br, and N-bromosuccinimide) on the oxidation of benzyl alcohol is reported. The results show that benzyl alcohol was selectively converted to benzaldehyde in 71.9% yield within 4 h in acetonitrile. Control experiments performed without catalyst and the corresponding metal salt as catalyst produced no benzaldehyde in the reaction mixture. Mild reaction conditions, high yields of the products, short reaction time, no further oxidation to the corresponding carboxylic acids, high selectivity, and inexpensive reagents make this catalytic system a useful oxidation method for benzyl alcohol.