A new bow-tie: Synthesis and X-ray structure of CO2Ru3(m5-h2,h2-PhC2C2Ph)(CO)14, which shows a remarkable and unusual asymmetry in the solid state

Abstract

The reaction between Ru3(μ3-η2-PhC2C2Ph)(μ-CO)(CO)9 and Co2(CO)8 affords the pentametal cluster Co2Ru3(μ5-η2,η2-PhC2C2Ph)(CO)14 in quantitative yield. The X-ray determined molecular structure consists of a Co2Ru3 bow-tie cluster which is straddled by the PhC2C2Ph ligand, interacting with all five metal atoms via the two Ctriple bond; length as m-dashC triple bonds, each of which is attached in the 2σ(2Ru), π(Co) bonding mode. Of the 14 CO groups, one bridges one Co-central Ru bond in one half of the molecule, while two are found semibridging the central Ru---Co and —Ru vectors in the other half of the molecule. In the solid state, there is thus a curious and remarkable asymmetry between the two halves of the molecule, although in solution at room temperature the molecule appears to be symmetrical.