Application in the cyclohexane oxidation of a scorpionate oxovanadium(IV) complex: synthesis,structure, and properties of VO(C5H7O2)(BC9H7N6I3)

An oxovanadium(IV) complex, VO(C₅H₇O₂)(BC₉H₇N₆I₃), derived from hydrotris(4-iodinpyrazolyl)borate was designed and synthesized at room temperature in methanol. The complex was characterized by elemental analysis, IR spectra, UV-Vis spectroscopy, and single-crystal X-ray diffraction. The structural analysis shows that the vanadium(IV) center possesses a distorted-octahedral geometry with a N₃O₃ core, containing a tridentate hydrotris(4-iodinpyrazolyl)borate with nitrogen as three donors. The complex is the first structurally characterized example of a vanadium(IV) complex with hydrotris(4-iodinpyrazolyl)borate. It was used as a catalyst for cyclohexane oxidation under mild conditions and the effects of a variety of factors such as amount of acid and H₂O₂, the kind of solvent, as well as temperatures were evaluated; the maximum turnover number value reaches 321.