Mechanism of C-H Bond Oxidation by a Monooxoruthenium(V) Complex

Article abstract of DOI:10.1039/DT9910001259

The complex VL(O)>²⁺ bis<2-(2-pyridyl)ethyl>amine> was found to be a very active stoichiometric oxidant towards variuos hydrocarbons.Oxidation of alcohols was studied either in 0.1 mol dm^-3 HClO4 or CH3CN, the observed rate law being rate = kV>.The second-order rate constants for various alcohols follow the order benzylic > secondary > primary alcohols.Kinetic isotope effects (k_h/k_D) of 5.9 and 5.3 were found for benzylic alcohol and PrⁱOH respectively.Similar kinetic studies for the oxidation of tetrahydrofuran gave k_H/k_D = 6.8.Stoichiometric oxidation of saturated alkanes in acetonitrile gave tertiary alcohols exclusively or ketones when only methylene groups are present.The measured k_H/k_D for the oxidation of cyclohexane determined from competitive oxidation experiments was 5.3.No cyclohexyl chloride was found when the oxidation of cyclohexane was carried out in the presence of CCl4.The mechanism of C-H bond oxidation by Ru^V=O is discussed.