Oxygen Reduction with a Bifunctional Iridium Dihydride Complex.
The iridium dihydride [Ir(H)2 (HPNP)](+) (PNP=N(CH2 CH2 PtBu2 )2 ) reacts with O2 to give the unusual, square-planar iridium(III) hydroxide [Ir(OH)(PNP)](+) and water. Regeneration of the dihydride with H2 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 O2 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 MH bonds of a mononuclear metal complex.
Institut für Anorganische Chemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen (Germany).
Christoph
C
Schiwek
Institut für Anorganische Chemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen (Germany).
Jenni
J
Meiners
Insitut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Str. 7, 60438 Frankfurt am Main (Germany).
Moritz
M
Förster
Institut für Anorganische Chemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen (Germany).
Christian
C
Würtele
Insitut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Str. 7, 60438 Frankfurt am Main (Germany).
Martin
M
Diefenbach
Insitut für Anorganische und Analytische Chemie, Goethe-Universität, Max-von-Laue-Str. 7, 60438 Frankfurt am Main (Germany). max.holthausen@chemie.uni-frankfurt.de.
Max C
MC
Holthausen
Institut für Anorganische Chemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen (Germany). sven.schneider@chemie.uni-goettingen.de.
Sven
S
Schneider
density functional calculations; hydrides; iridium; oxygen; pincer ligands