title: Oxidative degradation of the organometallic iron(II) complex [Fe{bis[3-(pyridin-2-yl)-1H-imidazol-1-yl]methane}(MeCN)(PMe3)](PF6)2: structure of the ligand decomposition product trapped via coordination to iron(II).
abstract: Iron is of interest as a catalyst because of its established use in the Haber-Bosch process and because of its high abundance and low toxicity. Nitrogen-heterocyclic carbenes (NHC) are important ligands in homogeneous catalysis and iron-NHC complexes have attracted increasing attention in recent years but still face problems in terms of stability under oxidative conditions. The structure of the iron(II) complex [1,1'-bis(pyridin-2-yl)-2,2-bi(1H-imidazole)-κN(3)][3,3'-bis(pyridin-2-yl-κN)-1,1'-methanediylbi(1H-imidazol-2-yl-κC(2))](trimethylphosphane-κP)iron(II) bis(hexafluoridophosphate), [Fe(C17H14N6)(C16H12N6)(C3H9P)](PF6)2, features coordination by an organic decomposition product of a tetradentate NHC ligand in an axial position. The decomposition product, a C-C-coupled biimidazole, is trapped by coordination to still-intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions.
authors.affiliation: Chair of Inorganic Chemistry/Molecular Catalysis, Catalysis Research Center and Department of Chemistry, Technische Universität München, Ernst-Otto-Fischer-Strasse 1, 85747 Garching bei München, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Haslinger
authors.affiliation: Chair of Inorganic Chemistry/Molecular Catalysis, Catalysis Research Center and Department of Chemistry, Technische Universität München, Ernst-Otto-Fischer-Strasse 1, 85747 Garching bei München, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Pöthig
authors.affiliation: Chair of Inorganic Chemistry/Molecular Catalysis, Catalysis Research Center and Department of Chemistry, Technische Universität München, Ernst-Otto-Fischer-Strasse 1, 85747 Garching bei München, Germany.
authors.forename: Mirza
authors.initials: M
authors.lastname: Cokoja
authors.affiliation: Chair of Inorganic Chemistry/Molecular Catalysis, Catalysis Research Center and Department of Chemistry, Technische Universität München, Ernst-Otto-Fischer-Strasse 1, 85747 Garching bei München, Germany.
authors.forename: Fritz E
authors.initials: FE
authors.lastname: Kühn
keywords: N-heterocyclic carbenes (NHC); crystal structure; ligand decomposition; organometallic iron(II) complex; oxidative degradation