Synthesis of a series of hexanuclear ruthenium carbido cluster alkynes under mild conditions: X-ray structure analyses of the complexes [Ru6C(CO)15(µ3-η2-PhCCH)] and [Ru6C(CO)15(µ3-η2-PhCCMe)]

Abstract

The reaction of [Ru₆C(CO)₁₆]^2–(1) with alkynes in the presence of [Fe(cp)₂]BF₄(cp =η⁵-C₅H₅) or FeCl₃ gives the alkyne cluster derivatives [Ru₆C(CO)₁₅(µ₃-η²-RCCR′)][R = R′= H (2), Me (3), Et (4), or Ph (5); R ≠ R′, H and Ph (6), Me and Ph (7)] as the respective major products at room temperature. Prolonged heating of the cluster [Ru₆C(CO)₁₅(µ₃-η²-PhCCH)](6) in toluene over 3 d converts it into [Ru₆C(CO)₁₅(µ-H)(CCPh)](8), with hydride migration from the organo-fragment to a ruthenium metal centre. The structure of complexes (6) and (7) have been established by X-ray diffraction studies which show the alkyne ligands bonding to triangular ruthenium faces in a µ₃-η² mode.