title: Photolytic water oxidation catalyzed by a molecular carbene iridium complex.
abstract: The complex IrCl(2)(Cp*)(trz) (trz = triazolylidene), 2, was prepared from readily available 1,3-dimethyl-4-phenyl-1,2,3-triazolium salt. Under basic conditions, the C-bound phenyl group readily cyclometalates, while under acidic conditions, cyclometalation is reversed. The sensitivity of the C(aryl)-Ir bond but not the C(trz)-Ir bond towards acidolysis provided a basis for using 2 as a catalyst in Ce(IV)-mediated water oxidation. The catalytic activity is characterized by a robust catalytic cycle, affording excellent turnover numbers (TON > 20,000). Under cerium-free conditions and in the presence of hematite as a photoelectrode, light-induced activity was observed. The photoelectrochemical reaction is strongly pH-dependent, which requires pH adjustments when running multiple cycle experiments to regenerate the catalytic activity. Analogous chelating complexes display better stability and higher catalytic activity than the monodentate complex 2.
authors.affiliation: School of Chemistry & Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Ana
authors.initials: A
authors.lastname: Petronilho
authors.forename: Mahfujur
authors.initials: M
authors.lastname: Rahman
authors.forename: James A
authors.initials: JA
authors.lastname: Woods
authors.forename: Haris
authors.initials: H
authors.lastname: Al-Sayyed
authors.forename: Helge
authors.initials: H
authors.lastname: Müller-Bunz
authors.forename: J M
authors.initials: JM
authors.lastname: Don MacElroy
authors.forename: Stefan
authors.initials: S
authors.lastname: Bernhard
authors.forename: Martin
authors.initials: M
authors.lastname: Albrecht