cis-bis(bipyridine)(dimethylglyoxime)ruthenium(II): an electrochemical andspectroscopic investigation of proton-coupled electron transfer

Reaction of cis-[Ru(bpy)(2)(Cl)(2)] (bpy = 2,2'-bipyridine) with AgSO3CF3 t hen 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 asymmetr y 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 dissociatio ns with pK(a1) 4.60 and pk(a2) 7.33. The potential versus pH diagram (Pourb aix 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.