(ETA-2-VINYL)TUNGSTEN(II) AND (ETA-3-ALLYL)TUNGSTEN(II) COMPLEXES CONTAINING A HYDRIDOTRIS(3,5-DIMETHYLPYRAZOLYL)BORATE LIGAND

Cationic alkyne complexes react with anionic nucleophiles to generate the eta-2 -vinyl complexes Tp'-(CO)2W(eta-2-RC=CRR'). Reaction of [Tp'(CO)2W(PhC=CH)][BF4] with P(OMe)3 produces a P(O)-(OMe)2-substituted eta-2-vinyl complex, Tp'(CO)2W[-eta-2-CPh=CHP(O)(OMe)2], which can be protonated at the oxygen to generate a cationic P(OH)(OMe)2-substituted eta-2-vinyl complex, {Tp'(CO)2W[eta-2-CPh= CHP(OH)(OMe)2]}[BF4]. Reaction of [Tp'(CO)2W(RC=CMe)][BF4] (R = Me, Ph) with LiBEt3H generates eta-3-allyl complexes via an eta-vinyl intermediate. Reaction of [Tp'(CO)2W(Phc=CMe)] [BF4] with LiCu(Bun)2 yields an eta-1-acyl complex, Tp'(CO)W(PhC=CMe)[eta-1-C(O)Bun], in which the alkyne ligand acts as a four-electron donor.