Details

Autor(en) / Beteiligte

• Peljo, Pekka
• Murtomäki, Lasse
• Kallio, Tanja
• Xu, Hai-Jun
• Meyer, Michel
• Gros, Claude P.
• Barbe, Jean-Michel
• Girault, Hubert H.
• Laasonen, Kari
• Kontturi, Kyösti

Titel

Biomimetic Oxygen Reduction by Cofacial Porphyrins at a Liquid–Liquid Interface

Ist Teil von

• Journal of the American Chemical Society, 2012-04, Vol.134 (13), p.5974-5984

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• Oxygen reduction catalyzed by cofacial metalloporphyrins at the 1,2-dichlorobenzene–water interface was studied with two lipophilic electron donors of similar driving force, 1,1′-dimethylferrocene (DMFc) and tetrathiafulvalene (TTF). The reaction produces mainly water and some hydrogen peroxide, but the mediator has a significant effect on the selectivity, as DMFc and the porphyrins themselves catalyze the decomposition and the further reduction of hydrogen peroxide. Density functional theory calculations indicate that the biscobaltporphyrin, 4,5-bis[5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrinyl)]-9,9-dimethylxanthene, Co2(DPX), actually catalyzes oxygen reduction to hydrogen peroxide when oxygen is bound on the “exo” side (“dock-on”) of the catalyst, while four-electron reduction takes place with oxygen bound on the “endo” side (“dock-in”) of the molecule. These results can be explained by a “dock-on/dock-in” mechanism. The next step for improving bioinspired oxygen reduction catalysts would be blocking the “dock-on” path to achieve selective four-electron reduction of molecular oxygen.