98353-93-6Relevant articles and documents
Multiple Electron Oxidation of Phenols by an Oxo Complex of Ruthenium(IV)
Seok, Won K.,Meyer, Thomas J.
, p. 7358 - 7367 (2007/10/02)
The kinetics of oxidation of phenol and alkylated phenol derivatives by (2+) and (2+) (bpy is 2,2'-bipyridine and py is pyridine) to give the corresponding quinones have been studied in aqueous solution and in acetonitrile.The reactions are first order in both phenol and Ru(IV)=O(2+) or Ru(III)-OH(2+).They proceed via a detectable intermediate, which is a Ru(II) complex. 18O isotopic labeling experiments show that transfer of the oxo group from Ru(IV)=O(2+) to phenol is quantitative.The reactions are facile.With Ru(IV)=O(2+) as oxidant k(25 deg C, CH3CN) = 1.9 (+/-0.4) E2M-1s-1; with Ru(III)-OH(2+) as oxidant k(25 deg C, CH3CN) = 4.0 (+/-0.4) E1M-1s-1.On the basis of the rate laws, the magnitude of OH/OD and CH/CD kinetic isotope effects, and the 18O labeling results, the most reasonable mechanisms for oxidation of phenol by Ru(IV)=O(2+) appears to be electrophilic attack on the aromatic ring.For Ru(III)-OH(2+), oxidation appears to occur by CH/H atom transfer in CH3CN and OH/H atom transfer in water.
