The use of an electrogenerated cobalt(I) porphyrin for the homogeneous catalytic reduction of dioxygen in dimethylformamide. Reactions of ((TMpyP)Co sup II ) sup 4+ and ((TMpyP)Co sup I ) sup 3+ where TMpyP = meso-tetrakis(1-methylpyridinium-4-yl)porphyrin

Journal Article · Wed Oct 24 04:00:00 EDT 1990 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00178a005· OSTI ID:6286973

Sazou, D; Araullo-McAdams, C; Han, B C; Franzen, M M; Kadish, K M ^[1]

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1. Univ. of Houston, TX (USA)

The one-electron catalytic reduction of dioxygen by electrogenerated meso-tetrakis(1-methylpyridinium-4-yl)-porphinatocobalt(I), ((TMpyP)Co{sup I}){sup 3+}, was investigated by cyclic voltammetry, controlled potential coulometry, rotating ring-disk voltammetry, ESR, and UV-visible spectroelectrochemistry. The first reduction of ((TMpyP)Co{sup II}){sup 4+} in DMF containing 0.1 M tetrabutylammonium perchlorate occurs at E{sub 1/2} = {minus}0.49 V and leads to the formation of ((TMpyP)Co{sup I}){sup 3+}. This cobalt(I) complex is stable under an N{sub 2} atmosphere but in the presence of dissolved O{sub 2} is converted to ((TMpyP)Co{sup II}(O{sub 2}{sup {minus}})){sup 3+}, which is also stable at all potentials up to the reduction of free O{sub 2} (i.e., about {minus}0.80 to {minus}0.90 V vs SCE). A catalytic reduction of dioxygen occurs at E{sub p} = {minus}0.50 V by cyclic voltammetry (scan rate = 0.1 V s{sup {minus}1}) in DMF solutions containing ((TMpyP)Co{sup II}){sup 4+} and benzoic anhydride under O{sub 2}. The homogeneous reactions of ((TMpyP)Co{sup II}){sup 4+} and electrogenerated ((TMpyP)Co{sup I}){sup 3+} with O{sub 2} or O{sub 2}{sup {minus}} were characterized and monitored by ESR and UV-visible spectroscopic techniques.

• OSTI ID: 6286973
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 112:22; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMIDES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
COBALT COMPLEXES
COMPLEXES
DATA
ELECTRON SPIN RESONANCE
ELEMENTS
EXPERIMENTAL DATA
FORMAMIDE
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
MAGNETIC RESONANCE
MEASURING METHODS
NONMETALS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN
PORPHYRINS
REDUCTION
RESONANCE
TRANSITION ELEMENT COMPLEXES
VOLTAMETRY