title: Synthesis and characterization of new iridium photosensitizers for catalytic hydrogen generation from water.
abstract: Novel phenylazole ligands were applied successfully in the synthesis of cyclometalated iridium(III) complexes of the general formula [Ir(phenylazole)(2)(bpy)]PF(6) (bpy=2,2'-bipyridine). All complexes were fully characterized by NMR, IR, and MS spectroscopic studies as well as by cyclic voltammetry. Three crystal structures obtained by X-ray analysis complemented the spectroscopic investigations. The excited-state lifetimes of the iridium complexes were determined and showed to be in the range of several hundred ns to multiple µs. All obtained iridium complexes were active as photosensitizers in catalytic hydrogen evolution from water in the presence of triethylamine as a sacrificial reducing agent. Applying an in situ formed iron-based water reduction catalyst derived from [HNEt(3)](+) [HFe(3)(CO)(11)](-) and tris[3,5-tris-(trifluoromethyl)-phenyl]phosphine as the ligand, [Ir(2-phenylbenz-oxazole)(2)-(bpy)]PF(6) proved to be the most efficient complex giving a quantum yield of 16% at 440 nm light irradiation.
authors.affiliation: Leibniz Institute for Catalysis, Albert-Einstein-Strasse 29a, 18059 Rostock, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Gärtner
authors.forename: Stefania
authors.initials: S
authors.lastname: Denurra
authors.forename: Sebastian
authors.initials: S
authors.lastname: Losse
authors.forename: Antje
authors.initials: A
authors.lastname: Neubauer
authors.forename: Albert
authors.initials: A
authors.lastname: Boddien
authors.forename: Anilkumar
authors.initials: A
authors.lastname: Gopinathan
authors.forename: Anke
authors.initials: A
authors.lastname: Spannenberg
authors.forename: Henrik
authors.initials: H
authors.lastname: Junge
authors.forename: Stefan
authors.initials: S
authors.lastname: Lochbrunner
authors.forename: Matthias
authors.initials: M
authors.lastname: Blug
authors.forename: Sascha
authors.initials: S
authors.lastname: Hoch
authors.forename: Jens
authors.initials: J
authors.lastname: Busse
authors.forename: Serafino
authors.initials: S
authors.lastname: Gladiali
authors.forename: Matthias
authors.initials: M
authors.lastname: Beller