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.

Simple Access to the Non‐Oxidizing Lewis Superacid PhF→Al(ORF)3 (RF=C(CF3)3)

“…[ 28] The geometry about the central aluminum ion Al1 can be described as distorted tetrahedral or 4(+1). The fifth contact opposite to the coordinating fluorobenzene molecule derives from a CF 3 group but is quite long (2.770 (8) ), which illustrates the improved stability of the adduct complex compared to the calculated data from free Al(OR F ) 3 , with CF 3 contacts of about 2.13 (see above).…”

Intramolecular Metal–Fluorocarbon Coordination, CF Bond Activation and Lanthanoid–Fluoride Clusters with Tethered Polyfluorophenylamide Ligands

“…[10][11][12] In addition, BA C H T U N G T R E N N U N G (C 6 F 5 ) 4 À and related anions can act as C(Ar)-F-Ln donors, often chelating through two fluorine atoms. [13][14][15] Even discrete fluorine-bonded complexes between [ScA C H T U N G T R E N N U N G (C 5 Me 5 ) 2 ]…”

“…+ and fluorobenzene or 1,2-difluorobenzene have been characterised as BPh 4 À salts, [14] whilst the encapsulation of La 3 + in a cage with polyfluoroarene, N-A C H T U N G T R E N N U N G (amine) and OA C H T U N G T R E N N U N G (ether) donor atoms has closer interactions with F than O or N. [16] (There is also related structural chemistry involving fluoroalkyl groups. [17,18] ) Such complexes are poised for CÀF activation, since the very strong CÀF bonds [19,20] are weakened by coordination.…”

Er3+ and Eu3+ complexes with heptafluoroacetylacetone and tris(pentafluoro)phenylphosphine oxide: The role of the pentafluorophenyl group on the coordination geometry and on the electronic absorption spectra

“…However, to the best of our knowledge, very few studies have been devoted to the investigation of these effects on the structures of organometallic and coordination compounds [14][15][16], and in particular on the coordination sphere of compounds of lanthanide ions.…”