Syntheses and reactions of some cluster complexes containing C-4 ligands with iron, ruthenium and cobalt carbonyls

Some reactions of W(C=CC=CH)(CO)(3)Cp with metal cluster carbonyls have bee n studied. With Ru-3(CO)(10)(NCMe)(2) the initial product is Ru-3{mu(3)-HC2 C=C[W(CO)(3)Cp]}(mu-CO)(CO)(9), which readily transforms into Ru-3(mu-H){mu (3)-C2C=C[W(CO)(3)Cp]}(CO)(9). Similar chemistry is found with the dppm ana logue: three interconverting isomers of Ru-3(mu-H){mu(3)-C2C=C[W(CO)(3)Cp]} (mu-dppm)(CO)(7) can be detected in solution. Reactions of Ru-3(mu-H){mu(3) -C2C=C[W(CO)(3)Cp]}(CO)(9) with Ru-3(CO)(12) afforded {Ru-3(mu-H)(CO)(9)}(m u(3)-eta(2):mu(3)-eta(2)-C2C2){Ru2W(CO)(8)Cp}, while Fe-2(CO)(9) gave an an alogous product in which three of the ruthenium sites are partially occupie d by a total of one or two iron atoms; with Co-2(CO)(8) the vinylidene clus ter {CoRu2(CO)(9)}(mu(3)-eta(2):mu(3)-eta(2)-CCHC2){CoRuW(CO)(8)Cp} was for med, the cluster-bound hydride transferring to the C-4 ligand. The molecula r structures of five complexes have been determined by single-crystal X-ray studies. Theoretical calculations have rationalised the tendency for the f ormation of mu(3)-eta(2)-C-2 fragments in these C-4 clusters.