Two complexes containing 19-atom chains linking metal centres

The first example of a complex containing a C19 chain, {Co3(μ-dppm)(CO)7}{μ3-C(C≡C)9}{W(CO)3Cp}, has been prepared in 22% yield from the Pd(0) / Cu(I)-catalysed reaction between I(C≡C)3I, W{C≡CC≡CAu(PPh3)}(CO)3Cp and Co3{μ3-C(C≡C)4Au(PPh3)}(μ-dppm)(CO)7. Other products also formed include {Co3(μ-dppm)(CO)7}{μ3-C(C≡C)6}{W(CO)3Cp} (32%), {Co3(μ-dppm)(CO)7}2{μ3:μ3-C(C≡C)xC} [x = 8 (6%) and 11 (5%)], containing respectively C13, C18 and C24 chains, and {W(CO)3Cp}2{μ-(C≡C)x} (x = 4, 7) (traces). A second example of a 19-atom chain is found in Hg{(C≡C)4C[Co3(μ-dppm)(CO)7]}2, obtained in 24% yield from the reaction between Hg(OAc)2 and Co3{μ3-C(C≡C)4SiMe3}(μ-dppm)(CO)7 in the presence of NaOMe.