Electrochemical Properties of (η5-C5Me5)–Rhodium and –Iridium Complexes Containing Bis(pyrazolyl)alkane Ligands

The electrochemical properties of rhodium(III) 1-3 and iridium(III) 4-6 complexes containing bis(pyrazolyl)alkane ligands [MCp*Cl(R2C(3,5-R’2pz)2)]X (M = Rh (1) or Ir(4),R=R’=H,X=Cl;M=Rh(2)orIr(5), R=H,R’=Me,X=Cl;M=Rh(3)or Ir (6), R = Me, R’ = H, X = OTf; pz = pyrazolyl; Cp* =η5-C5Me5) were investigated by cyclic voltammetry and controlled potential electrolysis. They exhibit two sequential irreversible reductions assigned to the MIII → MII and MII → MI reductions, which are dependent on the methylation of the bis(pyrazolyl)alkane ligands.