cis-Bis(bipyridine)(dimethylglyoxime)ruthenium(II): an electrochemical and spectroscopic investigation of proton-coupled electron transfer

Reaction of cis-[Ru(bpy)2(Cl)2] (bpy=2,2′-bipyridine) with AgSO3CF3 then dimethylglyoxime (dmgH2) results in the formation of cis-[Ru(bpy)2(dmgH2)]2+. The cis geometry of the complex is confirmed by the asymmetry of the 1H and 13C NMR spectra. The oxime ligand of the isolated complex is doubly protonated, enabling the complex to undergo two acid dissociations with pKa1 4.60 and pKa2 7.33. The potential versus pH diagram (Pourbaix diagram) shows that the complex is capable of up to two proton and two electron transfers.