title: Electrocatalytic reduction of ROOH by iron porphyrins.
abstract: Electrocatalytic reduction of a series of chemical oxidants of different power (tert-butyl hydroperoxide, potassium peroxomonosulfate, peracetic acid, and m-chloroperbenzoic acid) at iron-porphyrin-modified graphite electrodes is studied in buffered aqueous solutions by rotating disk and ring-disk voltammetry. Both ferric and ferrous porphyrins are catalytically active. Turnover of ferric catalysts is slower than that of the ferrous analogues and involves competing catalytic reduction and disproportionation. The kinetic data are consistent with reactant binding being the rate-determining step in catalysis by Fe(III). In catalysis by Fe(II), the turnover is controlled by the first electron transfer. The covalently linked proximal imidazole ligand is found to be crucial for achieving the Fe(III) catalysis.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, California 94305, USA. jpc@stanford.edu
authors.forename: James P
authors.initials: JP
authors.lastname: Collman
authors.forename: Marina
authors.initials: M
authors.lastname: Kaplun
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Sunderland
authors.forename: Roman
authors.initials: R
authors.lastname: Boulatov
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D004563:Electrochemistry; D005290:Ferric Compounds / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D007700:Kinetics; D008665:Metalloporphyrins / Q000737:chemistry*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry
chemical_list: D002264:Carboxylic Acids; D005290:Ferric Compounds; D005296:Ferrous Compounds; D008665:Metalloporphyrins; D010545:Peroxides