title: Naked (C5Me5)2M cations (M = Sc, Ti, and V) and their fluoroarene complexes.
abstract: The ionic metallocene complexes [Cp*(2)M][BPh(4)] (Cp* = C(5)Me(5)) of the trivalent 3d metals Sc, Ti, and V were synthesized and structurally characterized. For M = Sc, the anion interacts weakly with the metal center through one of the phenyl groups, but for M = Ti and V, the cations are naked. They each contain one strongly distorted Cp* ligand, with one (V) or two (Ti) agostic C-H...M interactions involving the Cp*Me groups. For Sc and Ti, these Lewis acidic species react with fluorobenzene and 1,2-difluorobenzene to yield [Cp*(2)M(kappaF-FC(6)H(5))(n)][BPh(4)] (M = Sc, n = 2; M = Ti, n = 1) and [Cp*(2)M(kappa(2)F-1,2-F(2)C(6)H(4))][BPh(4)], the first examples of kappaF-fluorobenzene and kappa(2)F-1,2-difluorobenzene adducts of transition metals. With the perfluorinated anion [B(C(6)F(5))(4)](-), both Sc and Ti form [Cp*(2)M(kappa(2)F-C(6)F(5))B(C(6)F(5))(3)] contact ion pairs. The nature of the metal-fluoroarene interaction was studied by density functional theory (DFT) calculations and by comparison with the corresponding tetrahydrofuran (THF) adducts and was found to be predominantly electrostatic for all metals studied.
authors.affiliation: Center for Catalytic Olefin Polymerization, Stratingh Institute for Chemistry and Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Marco W
authors.initials: MW
authors.lastname: Bouwkamp
authors.forename: Peter H M
authors.initials: PH
authors.lastname: Budzelaar
authors.forename: Jeroen
authors.initials: J
authors.lastname: Gercama
authors.forename: Isabel
authors.initials: I
authors.lastname: Del Hierro Morales
authors.forename: Jeanette
authors.initials: J
authors.lastname: de Wolf
authors.forename: Auke
authors.initials: A
authors.lastname: Meetsma
authors.forename: Sergei I
authors.initials: SI
authors.lastname: Troyanov
authors.forename: Jan H
authors.initials: JH
authors.lastname: Teuben
authors.forename: Bart
authors.initials: B
authors.lastname: Hessen
mesh_terms: D002412:Cations / Q000737:chemistry; D018360:Crystallography, X-Ray; D005464:Fluorobenzenes / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D012538:Scandium / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*; D014639:Vanadium / Q000737:chemistry*
chemical_list: D002412:Cations; D005464:Fluorobenzenes; D008024:Ligands; D009942:Organometallic Compounds; D028561:Transition Elements; D014639:Vanadium; D014025:Titanium; D012538:Scandium