Chain‐Like Tetra‐, Penta‐ and Heptanuclear Cyanide‐Bridged Complexes by Attachment of Organometallic Cyanides to M2, M3 and M5 Units

Attachment of the “ligands” [Cp(dppe)Fe‐CN], [Cp(PPh3)2Ru‐CN], [Cp(CO)2Fe‐CN] and [(CO)5M‐CN]−, (where M = Cr, Mo, W) to the polymetallic centres [Ru2(OAc)4]+, [Co3(dpa)4]2+ and [Ni5(tdpa)4]2+ yielded two tetra‐, three penta‐ and five heptanuclear complexes with chain‐like linear arrangements of the metal ions and the bridging cyanide ligands, as proved by the structure determination of [Ni5(tdpa)4{Cp(dppe)2Fe‐CN}2](PF6)2. IR and CV data show that the Ru2, Co3 and Ni5 centres of these complexes withdraw electron density from the external organometallic units. This prevents electronic interactions between the two terminal metal ions, yet allows multistep one‐ and two‐electron redox processes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)