title: An iron(ii) hydride complex of a ligand with two adjacent β-diketiminate binding sites and its reactivity.
abstract: After lithiation of PYR-H2 (PYR = [(NC(Me)C(H)C(Me)NC6H3(iPr)2)2(C5H3N)](2-)) - the precursor of an expanded β-diketiminato ligand system with two binding pockets - with KN(TMS)2 the reaction of the resulting potassium salt with FeBr2 led to a dinuclear iron(ii) bromide complex [(PYR)Fe(μ-Br)2Fe] (1). Through treatment with KHBEt3 the bromide ligands could be replaced by hydrides to yield [PYR)Fe2(μ-H)2] (2), a distorted analogue of known β-diketiminato iron hydride complexes, as evidenced by NMR, Mößbauer and X-ray absorption spectroscopy, as well as by its reactivity: for instance, 2 reacts with the proton source lutidinium triflate via protonation of the hydride ligands to form an iron(ii) product [(PYR)Fe2(OTf)2] (4), while CO2 inserts into the Fe-H bonds generating the formate complex [(PYR)Fe2(μ-HCOO)2] (5); in the presence of traces of water partial hydrolysis occurs so that [(PYR)Fe2(μ-OH)(μ-HCOO)] (6) is isolated. Altogether, the iron(ii) chemistry supported by the PYR(2-) ligand is distinctly different from the one of nickel(ii), where both, the arrangement of the two binding pockets and the additional pyridyl donor led to diverging features as compared with the corresponding system based on the parent β-diketiminato ligand.
authors.affiliation: Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Str. 2, 12489 Berlin, Germany. christian.limberg@chemie.hu-berlin.de.
authors.forename: Henrike
authors.initials: H
authors.lastname: Gehring
authors.forename: Ramona
authors.initials: R
authors.lastname: Metzinger
authors.forename: Beatrice
authors.initials: B
authors.lastname: Braun
authors.forename: Christian
authors.initials: C
authors.lastname: Herwig
authors.forename: Sjoerd
authors.initials: S
authors.lastname: Harder
authors.forename: Kallol
authors.initials: K
authors.lastname: Ray
authors.forename: Christian
authors.initials: C
authors.lastname: Limberg
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005296:Ferrous Compounds / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D015204:Spectroscopy, Mossbauer
chemical_list: D056831:Coordination Complexes; D005296:Ferrous Compounds; D008024:Ligands; D007501:Iron