Ruthenium(II) alkynyl-hydride and ruthenium(II) bis(sigma-pyridylacetylide) as ligands and linkers for metal-metal-bonded complexes

The syntheses of new linear π-conjugated building blocks, ruthenium(II) alkynyl-hydride and bis(σ-pyridylacetylide) complexes, and their application to the formation of heterobimetallic units and oligomers incorporating metal–metal-bonded complexes are reported. The structure of a tetrametallic subunit has been determined by X-ray crystallography. Thermogravimetry shows a stabilization of the tetramer and the oligomers in comparison to the least stable starting material. Spectroscopic results and cyclovoltammetry indicate an N–M donor–acceptor interaction, but no extended electron delocalization along the backbone of the tetramer.