Phosphine Coordination to a Cobalt Diimine–Dioxime Catalyst Increases Stability during Light-Driven H 2 Production

The combination of cobalt diimine-dioxime complexes with a cyclometalated iridium photosensitizer gives efficient systems for hydrogen generation under visible-light irradiation using triethylamine as a sacrificial electron donor. Interestingly, the addition of triphenylphosphine (PPh3) to the mediu...

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Bibliographic Details
Published in:Inorganic chemistry 2012-02, Vol.51 (4), p.2115-2120
Main Authors: Zhang, Pan, Jacques, Pierre-André, Chavarot-Kerlidou, Murielle, Wang, Mei, Sun, Licheng, Fontecave, Marc, Artero, Vincent
Format: Article
Language:English
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Summary:The combination of cobalt diimine-dioxime complexes with a cyclometalated iridium photosensitizer gives efficient systems for hydrogen generation under visible-light irradiation using triethylamine as a sacrificial electron donor. Interestingly, the addition of triphenylphosphine (PPh3) to the medium results in a significant improvement of the stability of the system, with up to similar to 700 turnovers achieved within 10 h. UV-visible spectroscopic monitoring of the reaction allows identification of a PPh3-coordinated Co-I intermediate as the active species. Mechanistic issues regarding (i) the photogeneration of the Co-I species, (ii) the nature of the active species, and (iii) the influence of PPh3 on the H-2-evolution mechanism are discussed.
ISSN:0020-1669
1520-510X
1520-510X
DOI:10.1021/ic2019132