Electronic Communication in Oxidized Di- and Trinuclear Ruthenium Acetylide Complexes.

The electronic properties of a suite of di- and trinuclear ruthenium bis(acetylide)-based complexes incorporating phenylene and naphthylene bridges have been explored experimentally and computationally. The complexes, [{trans-Ru(dmpe)2(C≡CtBu)}2(μ2-C≡C(2,6-C10H6)C≡C)], [{trans-Ru(dmpe)2(C≡CtBu)}2(μ2-C≡C(2,7-C10H6)C≡C)], and [{trans-Ru(dmpe)2(C≡CtBu)}3(μ3-(C≡C)3(1,3,5C6H3)], were formed via the metathesis of terminal organic bisacetylenes with the methylruthenium complex, [trans-Ru(dmpe)2(CH3)(C≡CtBu)], in the presence of methanol and under mild conditions. Spectroelectrochemical analyses of these species showed that the linearly π-conjugated 2,6-naphthylene bridge enabled better electronic communication between redox-active ruthenium-acetylide sites than the cross-conjugated 2,7-naphthylene bridge.