Understanding the nature of reactive intermediates in the mechanism of oxidation of thioanisoles with Fe-TAML® activators of peroxides

INOR 686

Deboshri Banerjee, dbanerje@andrew.cmu.edu, Alexander D. Ryabov, and Terrence J. Collins, tc1u@andrew.cmu.edu. Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213-2683
Iron(III)-complexes of Tetra-Amido Macrocyclic Ligand(s) (Fe-TAML®) are a family of robust oxidation catalysts that can efficiently activate hydrogen peroxide and several organic peroxides to produce high valent reactive intermediates. The Fe-TAML activators of peroxide are highly effective for the oxidation of persistent pollutants, e.g. organic dyes, chlorophenols, and organophosphate pesticides among many others. Currently, studies are underway to understand the nature of, and characterize, the ‘real' reactive intermediate(s) derived from Fe-TAMLs. For our kinetic studies, we have chosen thioanisoles and substituted thioanisoles, which are predominantly oxidized to corresponding sulfoxides. Thioanisoles have been previously used in studies with heme and non-heme iron complexes to elucidate the nature of reactive intermediates, and distinguish between electron transfer and oxygen atom transfer mechanisms. Here we report an extensive kinetic analysis of the oxidation of thioanisoles with Fe-TAML/peroxides. The results indicate the existence of two intermediates, viz. a high-valent reactive monomer and a seemingly less reactive dimer, the latter being a predominant species at higher Fe-TAML concentrations. The kinetic data are particularly analyzed in an attempt to elucidate the possible nature of these intermediates.
 

General
7:00 PM-10:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster

Division of Inorganic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006