Abstract
A trinuclear carbonylruthenium complex, [Ru~3~(CO)~12~], was treated with diynes bearing ester, phenyl, or trimethylsilyl groups on the alkyne termini to give rise to various complexes. A diyne diester afforded a dinuclear ruthenacycle complex similar to known iron ferrole complexes and a mononuclear ruthenacyclopentadiene complex. The selectivity for the formation of these products varied depending on the ratio of the diyne diester toward [Ru~3~(CO)~12~]. When a phenyl‐substituted diyne was employed, a cyclopentadienone complex was formed together with the expected dinuclear ruthenacycle complex. In contrast, a bis(trimethylsilyl)diyne gave the corresponding cyclopentadienone complex as the only product. Treatment of the obtained ruthenabicycle complex with trimethylamine oxide (Me~3~NO) gave a mono(trimethylamine) complex, which was further converted into various phosphane complexes upon reaction with phosphanes in refluxing THF. The corresponding monophosphane complexes were obtained for all monodentate or bidentate phosphanes except for bis(diphenylphosphanyl)methane, which afforded a bridging bis(phosphane) complex. In contrast, when an isolated monodentate phosphane complex of 1,2‐bis(diphenylphosphanyl)ethane and diphenyl(2‐pyridyl)phosphane was treated with Me~3~NO, P‐P or P‐N chelate complexes were formed, respectively. The dinuclear mono(amine)ruthenacycle complex also reacted with dimethyl butynedioate (dimethyl acetylenedicarboxylate, DMAD) in refluxing THF to afford a novel μ‐η^2^‐alkyne complex together with the [2+2+2] cycloadduct between the diyne and DMAD. The highly electron‐deficient character of DMAD is imperative for the formation of the μ‐alkyne complex. Methyl propiolate and diphenylacetylene gave no corresponding μ‐alkyne complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)