title: Pentaarylcyclopentadienyl Iron, Cobalt, and Nickel Halides.
abstract: The preparation of new stable half-sandwich transition metal complexes, having a bulky cyclopentadienyl ligand C5(C6H4-4-Et)5 (Cp(Ar1)) or C5(C6H4-4-nBu)5 (Cp(Ar2)), is reported. The tetrahydrofuran (THF) adduct [Cp(Ar1)Fe(μ-Br)(THF)]2 (1a) was synthesized by reacting K[Cp(Ar1)] with [FeBr2(THF)2] in THF, and its molecular structure was determined by X-ray crystallography. Complex 1a easily loses its coordinated THF molecules under vacuum to form the solvent-free complex [Cp(Ar1)Fe(μ-Br)]2 (1b). The analogous complexes [Cp(Ar1)Co(μ-Br)]2 (2), [Cp(Ar1)Ni(μ-Br)]2 (3), and [Cp(Ar2)Ni(μ-Br)]2 (4) were synthesized from CoBr2 and [NiBr2(1,2-dimethoxyethane)]. The mononuclear, low-spin cobalt(III) and nickel(III) complexes [Cp(Ar2)MI2] (5, M = Co; 6, M = Ni) were prepared by reacting the radical Cp(Ar2) with NiI2 and CoI2. The complexes were characterized by NMR and UV-vis spectroscopies and by elemental analyses. Single-crystal X-ray structure analyses revealed that the dimeric complexes 1a, 1b, and 3 have a planar M2Br2 core, whereas 2 and 4 feature a puckered M2Br2 ring.
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg , D-93040 Regensburg, Germany.
authors.forename: Uttam
authors.initials: U
authors.lastname: Chakraborty
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg , D-93040 Regensburg, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Modl
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg , D-93040 Regensburg, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Mühldorf
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg , D-93040 Regensburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Bodensteiner
authors.affiliation: Institute of Inorganic Chemistry, University of Göttingen , D-37077 Göttingen, Germany.
authors.forename: Serhiy
authors.initials: S
authors.lastname: Demeshko
authors.affiliation: Stratingh Institute for Chemistry , Nijenborgh 4, 9747 AG Groningen, Netherlands.
authors.forename: Niels J C
authors.initials: NJ
authors.lastname: van Velzen
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg , D-93040 Regensburg, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Scheer
authors.affiliation: Stratingh Institute for Chemistry , Nijenborgh 4, 9747 AG Groningen, Netherlands.|Inorganic and Organometallic Chemistry, Friedrich Alexander University Erlangen-Nürnberg , D-91058 Erlangen, Germany.
authors.forename: Sjoerd
authors.initials: S
authors.lastname: Harder
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg , D-93040 Regensburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Wolf