Fully delocalized (ethynyl)(vinyl)phenylene-bridged diruthenium radical complexes.
Résumé
Diruthenium complexes [(X)(dppe)2Ru-C≡C-1,4-C6H4-CH:CH-RuCl(CO)(PiPr3)2] (1a,b, X = = Cl, C≡CPh) contg. an unsym. (ethynyl)(vinyl)phenylene bridging ligand were prepd. by alkyne insertion into Ru-H-bond and compared to their sym. 1,4-bis(ethynyl)phenylene- and 1,4-divinylphenylene-bridged congeners and their mononuclear alkynyl precursors. Electrochem. and UV/vis/NIR, IR, and EPR spectroscopic studies on the neutral complexes and their various oxidized forms indicate bridging ligand-centered oxidn. processes and uniform charge and spin delocalization over both dislike organoruthenium moieties despite differences in their intrinsic redox potentials. Comparison between the chloro and the phenylacetylide-terminated derivs. 1a,b suggests further that the conjugated organometallic π-system extends over the entire unsatd. backbone including the terminal ligand at the alkynyl ruthenium site. This paves the way to even more extended π-conjugated organoruthenium arrays for long-range electronic interactions. [on SciFinder(R)]
Mots clés
ESR spectra cation radical diruthenium conjugated vinylphenylene bridged acetylide
near IR spectra spectroelectrochem diruthenium vinylphenylene acetylide complex
redox potential electron communication cation radical diruthenium vinylphenylene acetylide
ruthenium vinyl acetylide binuclear phenylene bridged conjugated complex prepn