Some reactions of allenylidene-ruthenium cluster carbonyls with alkynes

Abstract

Reactions of Ru₃(μ-H)(μ₃-CCCPh₂)(μ-OH)(CO)₉ (1) with alkynes and 1,3-diynes are described. With HCCSiMe₃, sequential formation of Ru₃{μ₃-CH(SiMe₃)CHCCCPh₂}(μ-OH)(CO)₉ (3) and Ru₃{μ₃-Me₃SiCCHCHC(SiMe₃)CCCPh₂}(CO)₈ (4) occurred, whereas with HCCPh, the two isomeric complexes Ru₃(μ₃-CRCR′CR′CRCCCPh₂)(CO)₈ [R = Ph, H, (5a), R′ = H, Ph (5b)] were isolated. These are formed by insertion of the alkyne into an Ru–C bond, with migration of the cluster H atom to the organic ligand. For 5, elimination of the OH group with one alkyne H atom gives water. The metallabenzene complex Ru₃{μ₃-(FcCCH)₂CCCPh₂}(CO)₉ (6) was obtained from 1 and HCCFc. The allenyl cluster Ru₃{μ₃-Ph₂CCC(CPhCHPh)}(μ-OH)(CO)₉ (7) is formed from 1 and PhCCPh. The allenyl complex Ru₃{μ₃-Me₃SiCC(CCSiMe₃)CCCPh₂}(μ-OH)(CO)₉ (8), formed from 1 and Me₃SiCCCCSiMe₃, and with a structure analogous to that of 3, undergoes isomerisation on heating to yield Ru₃{μ₃-Ph₂CCCC(CCSiMe₃)CHSiMe₃}(μ-OH)(CO)₉ (9) by slippage of the organic ligand over the cluster. The reaction between 1 and FcCCCCFc affords Ru₃{μ₃-Ph₂CCCC(CCFc)CHFc}(μ-OH)(CO)₉ (10), with a structure analogous to that of 9.