Reaction of a polyphosphino ruthenium(II) acetate complex with Grignard reagents: Halogenation, alkylation and β-elimination

• A ruthenium complex, (PMe3)4Ru(H)OAc has been prepared via ligand exchange and purified through solvent partitioning.
• The conversion of (PMe3)4Ru(H)OAc to ruthenium alkyl hydride complexes (PMe3)4Ru(H)R is described.
• Alkylation occurs in competition with halide exchange from the Grignard reagent.

(PMe3)4Ru(H)OAc has been prepared from (PPh3)3Ru(H)OAc via phosphine exchange followed by solvent partitioning between acetonitrile and pentane. Complexes of the type (PMe3)4Ru(H)R (R = Et, nPr, nBu, iBu, H) have been synthesized through reaction with the corresponding Grignard reagents, RMgCl, and were found to be moderately stable provided the alkyl group is primary. Treatment with bulkier alkylmagnesium chlorides led instead to the dihydrido complex (PMe3)4RuH2. In some cases, the reaction was complicated by transfer of halide from the Grignard reagent to form, for example, (PMe3)4Ru(H)Cl.

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