Some chemistry of half-sandwich η-arene tungsten compounds

Abstract

The compounds [W(η-C₆H₅Me)(PMe₃)₃] and [W(η-C₆H₅Me){SiMe(CH₂PMe₂)₃}] have been prepared from [W(η-C₆H₅Me)₂] and tertiary phosphines. They are protonated by NH₄BF₄ to give [W(η-C₆H₅Me)(PMe₃)₃H]BF₄ and [W(η-C₆H₅Me){SiMe(CH₂PMe₂)₃}H]BF₄, respectively. Reaction of [W(η-C₆H₅Me)(PMe₃)₃] with HCl gas gives the diprotonated cation [W(η-C₆H₅Me)(PMe₃)₃H₂]²⁺. Treatment of [W(η-C₆H₅Me)(η-C₃H₅)(dmpe)]PF₆[dmpe = 1,2-bis(dimethylphosphino)ethane] with LiAlH₄ gives the η-methylcyclohexadienyl complex [W(η⁵-C₆H₆Me)(η-C₃H₅)(dmpe)], as a mixture of inseparable isomers. These have been characterised by multinuclear two-dimensional NMR spectroscopy. The fluorohydride [W(η-C₆H₅Me)(dmpe)H(F)] has also been prepared. The X-ray crystal structures of [W(η-C₆H₅Me)(PMe₃)₃H₂][PF₆]₂ and [W(η-C₆H₅Me)(dmpe)H(F)] have been determined.