Reactions of eta(5)-cyclopentadienylruthenium(II) complexes with gamma-hydroxyacetylenes

The complexes [CpRuL(2)Cl] (L = PPh(3), AsPh(3), SbPh(3)) react with the phenylacetylene, gamma-hydroxyacetylenes HC = CCR(1)R(2)OH (R(1) = R(2) = H, Me, and R(1) = Me, R(2) = Et; CR(1)R(2)OH = 1-hydroxycyclohexanol) and NaBF4 in methanol, to yield complexes of the type eta(1)-vinylidenes [CpL(2)Ru(+)(= C = CHR)], eta(1)-allenylidene [CpL(2)Ru(+)(= C = C = CR(1)R(2))], and dimeric allenylidene-vinyl and vinylidene-alkylidene complexes. These eta(1)-vinylidene and eta(1)-allenylidene complexes are reversibly deprotonated by sodium borohydride in methanol to yield the corresponding eta(1)-alkynyl complexes [CpL(2)Ru(C = CR)].