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 (dmgH(2)) results in the formation of cis-[Ru(bpy)(2)(dmgH(2))](2+). The cis geometry of the complex is confirmed by the asymmetry of the H-1 and C-13 NMR spectra. The oxime ligand of the isolated complex is doubly protonated, enabling the complex to undergo two acid dissociations with pK(a1) 4.60 and pk(a2) 7.33. The potential versus pH diagram (Pourbaix diagram) shows that the complex is capable of up to two proton and two electron transfers. (C) 2000 Elsevier Science S.A. All rights reserved.