Reactions of metalloalkynes 5: reinvestigation of the reaction of [{Ru(CO)2(η-C5H4R)}2(μ-CC)] with [Ru3(CO)10(μ-dppm)]

We have previously reported the reactions of the activated cluster compound, [Ru3(CO)10(dppm)] (1), with ethyne-1,2-diyl compounds, [{Ru(CO)2(η-C5H4R)}2(μ-CC)], (2a, R=H; 2b, R=CH3), which gave the new complexes [Ru5(μ5-CC)(η-C5H4R)2(dppm)(μ2-CO)2(CO)7], (3a, R=H; 3b, R=CH3). Our desire to extend the chemistry of these complexes required larger quantities of starting materials and in these syntheses we found that an additional complex, [Ru5(μ4-CC)(η-C5H5)2(dppm)(μ-CO)(CO)9] (4a), was formed. This apparently results from the reaction of 1 with 2, and is related to [Ru5(μ5-CC)(η-C5H5)2(dppm)(μ2-CO)2(CO)7] (3a) by the addition of a single carbonyl ligand. The reaction of complex 3b with CO was investigated and resulted in the isolation of [Ru4(μ4-CC)(η-C5H4Me)2(dppm)(CO)9] (5b) and the isolation of complex 4b, which was identified by comparison of its spectroscopic properties with that of 4a, in addition the 13CO labelling of complexes 3 resulted in the unequivocal assignment of the carbide resonances in their 13C-NMR spectra