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 HC≡CSiMe₃, sequential formation of Ru₃{μ₃-CH(SiMe₃)CHCC=CPh₂}(μ-OH)(CO)₉ ( 3) and Ru₃{μ₃-Me₃SiCCHCHC(SiMe₃)CC=CPh₂}(CO)₈ ( 4) occurred, whereas with HC≡CPh, the two isomeric complexes Ru₃(μ₃-CRCR’R’CRCC=CPh₂)(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) ₂CC=CPh₂}(CO)₉ ( 6) was obtained from 1 and HC≡CFc. The allenyl cluster Ru₃{μ₃-Ph₂CCC(CPh=CHPh)}(μ-OH)(CO)₉ ( 7) is formed from 1 and PhC≡CPh. The allenyl complex Ru₃{μ₃-Me₃SiCC(C≡CSiMe₃)CC=CPh₂}(μ-OH)(CO)₉ ( 8), formed from 1 and Me3SiC≡CC≡CSiMe₃, and with a structure analogous to that of 3, undergoes isomerisation on heating to yield Ru₃{μ₃-Ph₂CCCC(C≡CSiMe₃)=CHSiMe₃}(μ-OH)(CO)₉ ( 9) by slippage of the organic ligand over the cluster. The reaction between 1 and FcC≡CC≡CFc affords Ru₃{μ₃-Ph₂CCCC(C≡CFc)=CHFc}(μ-OH)(CO)₉ ( 10), with a structure analogous to that of 9.