The system iron(II)/mpzbpy mediates the H2O2 oxidation of cyclohexane and cyclooctene and the aerobic oxidative cleavage of ascorbic acid to oxalate

The iron complex generated in situ from Fe(CF3SO3)2 and the new tridentate N ligand mpzbpy (mpzbpy stands for 6-(3,5-dimethylpyrazol-1-ylmethyl)-6′-methyl-2,2′-bipyridine) mediates the room temperature oxidation of cyclohexane to cyclohexanol and cyclohexanone, and the epoxidation of cyclooctene to cyclooctene oxide. X-ray diffraction studies of single crystals obtained by reaction of iron(II) triflate with mpzbpy in methanol in the presence of ascorbic acid reveals the formation of a dinuclear complex, namely [Fe2(mpzbpy)2(C2O4)(CF3SO3)2] (1), where two iron(II) ions are bridged by an oxalato dianion originating from the oxidative cleavage of ascorbic acid. Magnetic susceptibility measurements of 1 show that the two metallic centres are weakly antiferromagnetically coupled, with a J value of −1.74(1) cm−1.

Graphical abstractA new iron complex generated in situ from Fe(CF3SO3)2 and the new tridentate N ligand 6-(3,5-dimethylpyrazol-1-ylmethyl)-6′-methyl-2,2′-bipyridine mediates the room temperature oxidation of cyclohexane to cyclohexanol and cyclohexanone, and the epoxidation of cyclooctene to cyclooctene oxide. The formation of a dinuclear complex, namely [Fe2(mpzbpy)2(C2O4)(CF3SO3)2] where two iron(II) ions are bridged by an oxalato dianion originating from the oxidative cleavage of ascorbic acid has been proven.Figure optionsDownload full-size imageDownload as PowerPoint slide