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.