Polymetallation of alkenes: Formation of some complexes containing branched chain carbon-rich ligands

Reactions of {(Ph3P)AuCtriple bond; length of mdashC}2Cdouble bond; length as m-dashC{Ctriple bond; length of mdashCAu(PPh3)}2 (1b), with Co3(μ-CBr)(μ-dppm)n(CO)9−2n (n = 0, 1) result in complete or partial elimination of AuBr(PPh3) to give the complexes {(OC)9Co3-μ3-CCtriple bond; length of mdashC}2Cdouble bond; length as m-dashC{Ctriple bond; length of mdashC-μ3-CCo3(CO)9}2 (3), trans-{(OC)7(μ-dppm)Co3-μ3-CCtriple bond; length of mdashC}(HCtriple bond; length of mdashC)Cdouble bond; length as m-dashC{Ctriple bond; length of mdashCAu(PPh3)}{Ctriple bond; length of mdashC-μ3-CCo3(μ-dppm)(CO)7} (4), {(OC)7(μ-dppm)Co3-μ3-CCtriple bond; length of mdashC}2Cdouble bond; length as m-dashC(Ctriple bond; length of mdashCH){Ctriple bond; length of mdashC-μ3-CCo3(μ-dppm)(CO)7} (5) and {(OC)7(μ-dppm)Co3-μ3-CCtriple bond; length of mdashC}2Cdouble bond; length as m-dashC{Ctriple bond; length of mdashCAu(PPh3)}{Ctriple bond; length of mdashC-μ3-CCo3(μ-dppm)(CO)7} (6), which have been identified by spectroscopic methods and in the cases of 3, 4 and 5, by single-crystal X-ray diffraction methods.