Abstract

The reaction of diazoindene (C9H6N2) with [Ru3(CO)12] in THF leads to the formation of the clusters [Ru3(CO)10(?5:?1-C 9H6)] (1), by the insertion of a C9H6 moiety into a Ru-Ru bond, [Ru3(CO)8(?5-C9H 6)2] (2), a trinuclear complex with an open Ru3 unit containing the 1,1?-bis(indenylidene) ligand, and two metallacyclic ruthenium trimers of formula [Ru3(CO)6-(?5:?1-C 9H6)3] (3 and 4). The cyclic trimers have stable chair- and twist-boat-like configurations similar to the boat-chair isomerism of cyclohexane. Both complexes are configurational rather than conformational isomers, because the boat-to-chair ring flip is hampered by the rigid nature of the Ru3C3 metallacycle. The structures of 2-4 have been established by X-ray crystallography.