Unexpected coupling between an (eta)5-indenyl ligand and alkenyl-vinylidene fragments: synthesis of unprecedented ((eta)6indene)ruthenium(II) metallacycles

Vinylidene complexes [Ru{=C=C(H)CR1R2CH2C(Me)=CH2}((eta)5-C9H7)(PPh3)2][BF4] undergo an intramolecular coupling between the alkenylvinylidene fragment and the (eta)5-indenyl ligand to afford indene-metallacyclic compounds (6a,b) in which the resulting functionalised indene group is (eta)6-coordinated to the metal.