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.