Cu(II) and Fe(III) Complexes Derived from N-Acetylpyrazine-2-Carbohydrazide as Efficient Catalysts Towards Neat Microwave Assisted Oxidation of Alcohols

The mononuclear Cu(II) complex [Cu((k NN′ O-HL)(H 2O) 2] ( 1) was synthesized using N-acetylpyrazine-2-carbohydrazide (H 2L) and characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray crystallography. Two Fe(III) complexes derived from the same ligand viz, mononuclear [Fe((k NN′ O-HL)Cl 2] ( 2) and the binuclear [Fe(k NN′ O-HL)Cl(μ-OMe)] 2 ( 3) (synthesized as reported earlier), were also used in this study. The catalytic activity of these three complexes ( 1– 3) was examined towards the oxidation of alcohols using tert-butyl hydroperoxide (TBHP) as oxidising agent under solvent-free microwave irradiation conditions. Primary and secondary benzyl alcohols (benzyl alcohol and 1-phenylethanol), and secondary aliphatic alcohols (cyclohexanol) were used as model substrates for this study. A comparison of their catalytic efficiency was performed. Complex 1 exhibited the highest activity in the presence of TEMPO as promoter for the oxidation of 1-phenylethanol with a maximum yield of 91.3% of acetophenone. View Full-Tex