Synthesis and electrochemical characterization of bimetallic ruthenium complexes with the bridging eta(2)(sigma,sigma)-1,3-butadiyne-1,4-diyl ligand

The bis(ruthenium)alkyne complex [cis-{RuCl (bpy)(2)(mu-C drop C)}](2) (1) was obtained by treatment of 1 equiv of either 1,4-bis(trimethylsilyl)-1,3-butadiyne or bis(trimetylsilyl)acetylene with 2 equiv of cis-[RuCl2(bpy)(2)]2H(2)O, NaF and NaBF4 salts in methanol/CH2Cl2 mixture (10/1) in 52% and 35% yields, respectively. H-1, (13){H} NMR and principally electrochemical analyses confirmed that the same product was obtained from the two reactions. Cyclic voltammetric analyses of (1) from 0 to 1.20V displays two one-electron quasi-reversible oxidation peaks attributed to the Ru(II)/Ru(III) couple. The redox processes are separated by 520 mV, indicating a significant electronic communication between the two metallic centers.11325225