Lina YE, Zhongping OU, Deying MENG, Mingzhu YUAN, Yuanyuan FANG, Karl M. KADISH

Electrochemistry of Fe(IV) and Mn(IV) corroles containing meso-dichlorophenyl substituents and the use of these compounds as catalysts for the electroreduction of dioxygen in acid media

Two meso-dichlorophenyl substituted metallocorroles were synthesized and characterized as to their electrochemical and spectroelectrochemical properties in dichloromethane, benzonitrile, and pyridine containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) as supporting electrolyte. The examined compounds are represented as (Cl2Ph)3CorFeIVCl and (Cl2Ph)3CorMnIVCl where (Cl2Ph)3Cor is the trianion of 5,10,15-tri(2,4-dichlorophenyl)corrole. Each metallocorrole was examined as to its catalytic activity for the electoreduction of dioxygen when coated on an edge-plane pyrolytic graphite electrode in 1.0 M HClO4. Cyclic voltammetry combined with linear sweep voltammetry at a rotating disk electrode (RDE) and a rotating ring disk electrode (RRDE) was utilized to evaluate the catalytic activity for the electroreduction of O2. The main O2 reduction product is hydrogen peroxide under the given experimental conditions.

Anahtar Kelimeler:

Metallocorroles, synthesis, electrochemistry, catalytic activity, dioxygen reduction

Electrochemistry of Fe(IV) and Mn(IV) corroles containing meso-dichlorophenyl substituents and the use of these compounds as catalysts for the electroreduction of dioxygen in acid media

Keywords:

Metallocorroles, synthesis, electrochemistry, catalytic activity, dioxygen reduction,

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(Cl2Ph)3CorMnCl 2. The procedure for synthesis of cpd 2 is the same as described above for cpd 1, but with 10 equivalents of Mn(OAc)2·4H2O utilized. The yield was 41%. UV-vis (PhCN): λmax,nm, ( ε× 10 −4 M −1 cm −1
) 316 (2.2), 364 (2.7), 422 (3.8), 593 (0.5). MS (MALDI-TOF): m/z 785.244, calcd. for [M-Cl]+ 785.214.
Instrumentation
Cyclic voltammetry was carried out at 298 K using an EG&G Princeton Applied Research (PAR) 173 poten- tiostat/galvanostat or a Chi-730C Electrochemistry Work Station. A 3-electrode system was used for cyclic voltammetric measurements and rotating disk voltammetry.
The working electrode was glassy carbon or graphite (Model MT134, Pine Instrument Co.)
A platinum counter electrode and a homemade saturated calomel reference electrode (SCE) were also used. The SCE was separated from the bulk of the solution by a fritted glass bridge of low porosity that contained the solvent/supporting electrolyte mixture.
until reproducible voltammograms were obtained.48,49