Redox characteristics and anion association behaviour of stereoisomeric forms of mono- and oligonuclear metal complexes using high pressure electrochemistry

Abstract

The effect of the presence of the anions PF6-, BF4-, ClO4-, and tosylate- on the potentials of the RuIII/II redox processes in a series of mono-, di-, and trinuclear complexes involving polypyridyl ligands are reported. The anions gives rise to a cathodic shift in the respective redox potentials in the sequence PF6- < BF4- ≈ ClO4- < tos-, with the magnitude of the shifts being largest for the tri-nuclear and smallest for the mononuclear species. In one dinuclear complex, a variation of anion was also observed to affect the difference in potentials between the [6+/5+] and [5+/4+] couples. These effects are consistent with known specific association of the anions with metal complexes of this t..