Synthesis of Mono- and Dinuclear Vanadium Complexes and Their Reactivity toward Dehydroperoxidation of Alkyl Hydroperoxides

Several vanadium­(V) complexes with either dipic-based or Schiff base ligands were synthesized. The complexes were fully characterized by elemental analysis, IR, 1H, 13C, and 51V NMR spectroscopy, as well as mass spectrometry and X-ray diffraction. Furthermore, they were tested toward their catalytic deperoxidation behavior and a significant difference between 4-heptyl hydroperoxide and cyclohexyl hydroperoxide was observed. In the case of 4-heptyl hydroperoxide, the selectivity toward the corresponding ketone was higher than with cyclohexyl hydroperoxide. DFT calculations performed on the vanadium complex showed that selective decomposition of secondary hydroperoxides with vanadium­(V) to yield the corresponding ketone and water is indeed energetically feasible. The computed catalytic path, involving cleavage of the O–O bond, hydrogen transfer, release of ketone/water, and finally addition of hydroperoxide, can proceed without the generation of radical species.