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Oxygen Reduction with a Bifunctional Iridium Dihydride Complex
Author(s) -
Schiwek Christoph,
Meiners Jenni,
Förster Moritz,
Würtele Christian,
Diefenbach Martin,
Holthausen Max C.,
Schneider Sven
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201504369
Subject(s) - iridium , chemistry , bifunctional , ligand (biochemistry) , catalysis , photochemistry , oxygen , metal , catalytic cycle , oxidative addition , organic chemistry , biochemistry , receptor
The iridium dihydride [Ir(H) 2 ( H PNP)] + (PNP=N(CH 2 CH 2 P t Bu 2 ) 2 ) reacts with O 2 to give the unusual, square‐planar iridium(III) hydroxide [Ir(OH)(PNP)] + and water. Regeneration of the dihydride with H 2 closes a quasi‐catalytic synthetic oxygen‐reduction reaction (ORR) cycle that can be run several times. Experimental and computational examinations are in agreement with an oxygenation mechanism via rate‐limiting O 2 coordination followed by H‐transfer at a single metal site, facilitated by the cooperating pincer ligand. Hence, the four electrons required for the ORR are stored within the two covalent MH bonds of a mononuclear metal complex.