Synthesis, reactivity, and X-ray structural characterization of a vanadium(III) oxidation pre-catalyst, (CpPOEtCo)VCl2(DMF)

Vanadium complexes are extensively used in the chemical industry as oxidation catalysts. During the course of our investigations into vanadium oxidation catalysis, the rich reactivity of a vanadium(III) scorpionate analogue complex, (CpPOEtCo)VCl2(DMF) (1), was investigated. The octahedrally coordinated 1 was prepared by mixing vanadium(III) chloride with Na(CpPOEtCo) in DMF. The crystal structure of 1 has been determined through X-ray diffraction. Complex 1, C20H42Cl2CoNO10P3V, crystallizes in the monoclinic space group P21/c with a = 38.566(9) Å, b = 9.499(2) Å, c = 18.149(4) Å, and β = 100.485(4)° with Z = 8. Complex 1 was found to be an effective pre-catalyst for the oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone. The reactivity studies, oxidative catalytic ability, as well as X-ray structural characterization of (CpPOEtCo)VCl2(DMF) will be discussed. ((CpPOEtCo) = [η5-cyclopentadienyltris(diethylphosphito-κ1P) cobaltate(III)−; DMF = N,N-dimethylformamide).

Graphical abstractThe synthesis, reactivity, and the catalytic ability of an octahedrally coordinated vanadium(III) scorpionate analogue complex are reported. The title complex makes use of the monoanionic facially coordinating ligand, CpPOEtCo−. (CpPOEtCo)VCl2(DMF) was found to be an effective catalyst in the oxidation of 3,5-di-tert-butyl catechol to the corresponding quinone. An X-ray crystal structure of (CpPOEtCo)VCl2(DMF) is also reported.Figure optionsDownload full-size imageDownload as PowerPoint slide