Kinetics and mechanisms of the oxidation of alcohols and hydroxylamines by hydrogen peroxide, catalyzed by methyltrioxorhenium, MTO, and the oxygen binding properties of cobalt Schiff base complexes

Primary and secondary alcohols were oxidized using hydrogen peroxide as an oxygen donor and methyltrioxorhenium (MTO) as a catalyst. The methylrhenium bis-peroxide, CH3Re(O)(eta2-O2)2(H 2O), was the dominant and reactive form of the catalyst. A hydride abstraction mechanism was proposed for this reaction based on a number of isotopic labeling experiments and a linear free energy relationship correlation. This H 2O2/MTO oxidation system was also used in the oxidation of secondary hydroxylamines to form nitrones or oxoammonium, ions. A mechanism was proposed where the nitrogen lone pair performs a nucleophilic attack on the rhenium bound peroxo-oxygen. This mechanism is supported by isotopic and steric effects. Co-catalytic systems were explored for the oxidation of alcohols using sodium bromide or oxoammonium. ions with the H2O2/MTO system.;The molecular oxygen binding rate constant for a variety of Co(III)salen derivatives was explored. The rate constant was determined using flash photolysis to dissociate oxygen from the pre-made Co(III)-O2. complex. A new twist to the rate constant determination of these reactions was also explored where in flash photolysis severs a cobalt-carbon bond of a Co(III)-alkyl complex, producing the Co(II) complex in the presence of O 2 and a radical scavenger.