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, [Ru,(CO)lo(dppm)] (1), with ethyne-1,2-diyl compounds, [{Ru(CO)(2)(eta-C5H4R)}(2)(mu-C=C)], (2a, R=H; 2b, R=CH3), which gave the new complexes [Ru-5(mu(5)-C=C)(eta-C5H4R)(2)(dppm)(mu(2)-CO)(2)(CO)(7)], (3a, R = H; 3b, R = CH,). 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, [Ru-5(mu(4)-CC)(eta-C5H5)(2)(dppm)(mu-CO)(CO)(9)] (4a), was formed. This apparently results from the reaction of 1 with 2, and is related to [Ru-5(mu(5)-C=C)(eta-C5H5)(2)(dppm)(mu(2)-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 [Ru-4(mu(4)-C=C)(eta-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 (CO)-C-13 labelling of complexes 3 resulted in the unequivocal assignment of the carbide resonances in their C-13-NMR spectra (C) 1999 Elsevier Science S.A. All rights reserved.