Synthesis and Reactivity of a Vanadium(III)−Methyl Complex Stabilized by Hexamethylsilazanate Ligands

Abstract

The vanadium(III) − Me complex [(Me 3 Si) 2 N] 2 VMe(THF) ( 1 ) was prepared by reaction of the corresponding V − Cl derivative with Me 2 Mg, and its X-ray crystal structure has been determined. The methyl complex reacts with 3 equiv of RNC (R = Bu t , Xylyl) to give isocyanide-coupled products, is oxidized by styrene oxide affording a V(IV) μ-O dimer, and on heating eliminates CH4 via metalation of a −N(SiMe3)2 ligand.

Reactivity of B(C6F5)3 with Oxovanadium(V) Complexes VOL3 (L = OCH2CF3, NEt2): Formation of the Organometallic Vanadium(V) Complex [VO(μ‐OCH2CF3)(OCH2CF3)(C6F5)]2 and the Lewis Acid Adduct [(Et2N)3VO·B(C6F5)3]

“…The 51 V chemical shifts for [VO(NEt 2 ) 3 ] and the borane adduct 2 (δ = −205 ppm and +57 ppm, respectively) are puzzling. If we consider that the sp 2 hybridization observed for the planar nitrogen atom of the NEt 2 ligands in 2 is unchanged in [VO(NEt 2 ) 3 ] before borane coordination (based on recent X‐ray diffraction studies of different dialkylamido vanadium( IV ) and vanadium( V ) complexes recently carried out by our group22 and others23) the observed deshielding shift could be attributed mainly to a decrease in electron density at the vanadium atom when the Lewis acid B(C 6 F 5 ) 3 is attached to the oxygen atom. A similar consequence of poorer π‐donation from O to V is also observed in the Lewis acid adducts [VO(CH 2 SiMe 3 ) 3− x (OSiPh 3 ) x ( x = 0−3)] with Al(CH 2 SiMe 3 ) 3 4b…”

Highlights in the Renaissance of Amidometal Chemistry

“…[185] The reactivity of this compound has been systematically and thoroughly investigated. [185,186] The reaction of 50 with KH is interesting because supramolecular organization occurs through agostic CÀH´´ṕ otassium interactions with the formation of a V 2 K 2 ensemble (Scheme 40). [187] Scheme 40.…”

Cationic Homoleptic Vanadium(II), (IV), and (V) Complexes Arising from Protonolysis of [V(NEt2)4]

“…[9] The environment around the metal is octahedral and the VÀN and VÀO distances (2.054 and 2.11 (average), respectively) are comparable to those in other vanadium compounds containing the bis(trimethylsilyl)amide ligand and a coordinated thf molecule. [10] The sum of the angles about each N center is close to 3608, indicating that the amide ligands are probably acting as three-electron donors. We also observe that a small, nonquantifiable amount of an uncharacterized green precipitate is present among the crystals of 2, providing evidence that the reaction is not simple.…”