Extending metal-capped polyynediyl molecular wires by insertion of inorganic metal units

Abstract

Several symmetric and asymmetric bis(metalla-diynediyl)ruthenium(II) complexes of the general formula trans-{L xRu} C≡CC≡C{Ru(dppe) 2}C≡CC≡C{RuL′ y} (L x, L′ y = (PPh 3) 2Cp, (dppe)Cp, (dppe)Cp*), containing Ru(dppe) 2 as the central linking group, have been successfully synthesized and characterized spectroscopically. DFT calculations show that their HOMO's are delocalized over the Ru-C 4-Ru-C 4-Ru chain, suggesting that there is electronic interaction between the terminal RuL x groups through the C 4 chains and the Ru(dppe) 2 center. Limited electrochemical measurements reveal that the complexes undergo a series of five stepwise reversible or quasi-reversible oxidation processes. © 2012 American Chemical Society.