Reactions of metalloalkynes: Part 6. Synthesis of open tetrametallic clusters. Reaction of [Ru(CO)4(ethene)] with ethyne-1,2-diyl compounds. Single crystal X-ray structural determinations of [Ru4(μ4-CC)(η-C5H4R)2(μ-CO)2(CO)8] (R=H, Me)

The reactions between [Ru(CO)4(η2-C2H4)], generated in situ, and ruthenium ethyne-1,2-diyl complexes, [{Ru(CO)2(η-C5H4R)}2(μ-CC)] (R=H, Me) have provided the new air-sensitive complexes [Ru4(μ4-CC)(η-C5H4R)2(μ-CO)2(CO)8] (R=H, Me) with a permetallated ethene structure, in good yield. The complexes were characterized spectroscopically and by single-crystal X-ray diffraction studies. They have an almost planar open geometry, rendering the C22− ligand accessible to reaction. The resonances attributed to the C22− ligand in the 13C{1H}-NMR spectra of the complexes have been unequivocally assigned with the aid of labeling experiments.