Dimetallapoly-yn-diylidynes: Ln M≡C-(C≡C)x -C≡MLn (x=0-4).

Synthetic routes to dimetallated Cx carbon wires in which two metals are separated by a linear carbon chain involving terminal metal-carbon triple bonds are described for the complexes [(Tp*)(CO)2 W≡C-(C≡C)n -C≡W(CO)2 (Tp*)] (Tp*=hydrotris(dimethylpyrazolyl)borate) where n=1, 3 or 4, joining the previously known examples with n=0, 1 and 2 to complete the series as models for linear carbyne C∞ .