Synthesis, characterization and electrochemistry of diruthenium complexes linked by aryl acetylide bridges

The reactions between Ru2(ap)4Cl and the appropriate lithiated aryl acetylene resulted in the complexes Ru2(ap)4(CC4-C6H4CCX) with X as SiMe3 (1), H (2) and Ru2(ap)4 (3), 1,3-[Ru2(ap)4(CC)]2(C6H4) (4), 1,3-[{Ru2(ap)4(CC)}2]C6H35-CCH (5) and 1-[Ru2(ap)4(CC)]C6H33,5-(CCH)2 (6), where ap is 2-anilinopyridinate. The spectroscopic and electrochemical properties of the new complexes have been assessed. Complexes 3, 4 and 6 display two-electron oxidation and reductions, implying the absence of any significant electronic interaction between the two Ru2(ap)4 units in these complexes.