Carbon‐Rich Ruthenium Complexes Containing Bis(allenylidene) and Mixed Alkynyl−Allenylidene Bridges (Eur. J. Inorg. Chem. 3/2005)

The cover picture shows two examples of stable polynuclear ruthenium systems containing delocalized carbon-rich bridges with unusual topologies. In this work, the synthesis, the spectroscopic and voltammetric studies of a new family of bis(allenylidene) and mixed allenylidene−acetylide complexes are presented. The nature of the reduced species, which are mainly ligand-centered, is pointed out by means of ESR and IR spectroscopy. The UV/Vis and electrochemical studies show the large influence of the bridge on the electronic interaction between the redox centers and the fine tuning of this property. These new conjugated molecules appear to be promising alternatives to the classical bis(acetylide) systems for the construction of metal-containing unsaturated oligomers or polymers to mediate electron-transfer processes. Details are discussed in the article by S. Rigaut, D. Touchard et al. on p. 447 ff.