Alkyne-based derivatives of [Ru6C(CO)(17)] and the stepwise synthesis of [Ru6C(CO)(13)(eta(5)-C(5)H(3)Ph(2))(mu(3)-CPh)]

A systematic synthetic route to the hexanuclear cluster compound [Ru6C(CO)(13)(eta 5-C(5)H(3)Ph(2))(mu(3)-CPh)] has been elaborated in which a number of stable intermediates have been isolated and characterised. The reaction of [Ru6C(CO)(17)] with Me(3)NO and phenylacetylene afforded the alkyne derivative [Ru6C(CO)(15)(PhC(2)H)] 1. Further treatment of 1 with Me(3)NO and an excess of phenylacetylene resulted in the formation of two isomers [Ru6C(Co)(14){C(Ph)CHC(Ph)CH}] 2 and [Ru6C(CO)(14){C(Ph)CHCHC(Ph)}] 3. Both contain five-membered metallocyclic rings formed by the head-to-head coupling of phenylacetylene in one isomer and the head-to-tail coupling in the other. Reaction of isomer 2 with Me(3)NO and phenylacetylene leads to [Ru6C(CO)(13)(eta(5)-C(5)H(3)Ph(2))-(mu(3)-CPh)] 4. The molecular structure of one of the isomers, 3, has been established by single-crystal X-ray crystallography.