Electrochemical studies on CuN₂O₂ chromophore

378-380Electrochemistry of Cu(nqo)2 and Cu(nqo)2.im (nqo = 1-nitroso-2-naphtholate anion, im ≡ imidazole) has been studied in acetonitrile by cyclic voltammetry and coulometry at platinum electrodes under N2 atmosphere. The square planar complex Cu(nqo)2 shows a quasireversible Cu(I/II) couple at -0.30 V and a quasireversible Cu(II/III) couple at 0.78 V vs saturated calomel electrode. This is the first report of the observation of a Cu(II/III) couple in a CuN2O2 chromophore. The potentials of both the couples are lowered in the pentacoordinated species Cu(nqo)2.im