114
J. Losada et al. / Inorganica Chimica Acta 321 (2001) 107–115
enhancement (by about 58.2%) observed at −0.34 V,
Acknowledgements
that electrodes modified with electropolymerized films
1
of CuL exhibit a significant electrocatalytic activity
The authors thank the Direcci o´ n General de Ense-
n˜ anza Superior e Investigaci o´ n Cient ´ı fica (project No.
PB-97-0001) for financial support of this research.
2
toward the reduction of O2.
It should be noted that the potentials for the reduc-
tion of O are nearly the same in acid and alkaline
2
solutions. This fact suggests that the rate-determining
step in the mechanism of oxygen reduction is the for-
mation of superoxide which is pH independent [40,41].
This may directly be reduced to H O or to H O as a
stable end product depending on the way the oxygen is
adsorbed onto the catalyst, involving in each case a
different number of metal-atoms in the interaction with
References
[
1] M.J. Carter, D.P. Rillema, F. Basolo, J. Am. Chem. Soc. 96
1974) 392.
2
2
2
(
[
[
2] D.F. Averill, R.F. Broman, Inorg. Chem. 17 (1978) 3389.
3] G.S. Patterson, R.H. Holm, Bioinorg. Chem. 4 (1975) 257.
[4] D.B. Rorabacher, M.J. Martin, M.J. Koenigbauer, M. Malik,
P.R. Schroeder, J.F. Eudicott, L.A. Ochrymowyez, in: K.D.
Karlin, J. Zubieta (Eds.), Copper Coordination Chemistry: Bio-
chemical and Inorganic Perspectives, Academic Press, New
York, 1983.
the O molecule [42].
2
These preliminary studies indicate the potential appli-
cation of electrodes modified with these polypyrrole
Cu(II) Schiff-base complexes in the field of catalysis.
[5] M.A. Elmorsi, M. Gabor, E. Barendrecht, J. Appl. Electrochem.
2
1 (1991) 1005.
[
6] B.R. Shaw, in: J.T. Stock, M.V. Orne (Eds.), Electrochemistry:
Past and Present. In: ACS Symposium Series, vol. 390, American
Chemical Society, Washington, DC, 1989, pp. 318–338.
[
[
[
7] C.R. Cabrera, H.D. Abru n˜ a, J. Electroanal. Chem. 209 (1986)
1
01.
8] S. Cosnier, A. Deronzier, J.C. Moutet, J. Electroanal. Chem. 207
1986) 315.
(
9] F. Garnier, G. Tourillon, M. Gazard, J.C. Dubois, J. Elec-
troanal. Chem. 148 (1983) 299.
[
[
10] J.P. Collin, A. Jouaiti, J.P. Sauvage, J. Electroanal. Chem. 286
1990) 75.
11] C.P. Andrieux, O. Haas, J.M. Saveant, J. Am. Chem. Soc. 108
1986) 8175.
(
(
[
12] M.D. Hobday, T.D. Smith, Chem. Rev. 9 (1972–1973) 311.
[
13] C.P. Horwitz, R.W. Murray, Mol. Cryst. Liq. Cryst. 160 (1988)
3
89.
14] K.A. Goldsby, J.K. Blabo, L.A. Hoferkamp, Polyhedron 8
1989) 113.
[15] L.A. Hoferkamp, K.A. Goldsby, Chem. Mater. 1 (1989) 348.
[16] F. Bedioui, E. Labbe, S. Gutierrez-Granados, J. Devynck, J.
Electroanal. Chem. 301 (1991) 267.
[
(
−
1
Fig. 9. Cyclic voltammograms at 100 mV s
for: (a) a bare gold
1
electrode; and (b) a gold electrode coated with a film of poly-[CuL ]
2
−
9
−2
(~=4×10
mol cm ) both in 0.1 M aqueous NaOH solution
saturated with oxygen.
[17] P. Capdevielle, M. Maumy, P. Audebert, B. Plaza, New J. Chem
1
8 (1994) 519 (and references cited therein).
18] C.E. Dahm, D.G. Peters, J. Simonet, J. Electroanal. Chem. 410
1996) 163.
[
(
[
[
[
[
19] C.E. Dahm, D.G. Peters, Anal. Chem. 66 (1994) 3117.
20] Y.K. Choi, J.K. Park, S. Jeon, Electroanalysis 11 (1999) 134.
21] A. Deronzier, J.C. Moutet, Coord. Chem. Rev. 147 (1996) 339.
22] J. Losada, I. del Peso, L. Beyer, J. Hartung, V. Fernandez, M.
M o¨ bius, J. Electroanal. Chem. 398 (1995) 89.
[
[
[
[
[
23] J. Losada, I. del Peso, L. Beyer, J. Electroanal. Chem. 447 (1998)
1
47.
24] J. Fagir, D.C. Borg, A. Forman, D. Dolphin, R.M. Felton, J.
Am. Chem. Soc. 92 (1970) 451.
25] M. Moran, I. Cuadrado, L. Pineda, J.R. Masaguer, J. Losada,
Inorg. Chim. Acta 169 (1990) 119.
26] D.D. Perrin, W.L.F. Amarego, D.R. Perrin, Purification of
Laboratory Chemicals, 2nd ed., Pergamon, New York, 1988.
27] A. Bach, L. Beyer, T. Gelbrich, K.H. Halmeier, C. Henning, M.
M o¨ bius, R. Richter, R. Szargan, V. Fernandez, J. Losada, Z.
Naturforsch., Teil B 51 (1996) 757.
−
1
Fig. 10. Cyclic voltammograms at 100 mV s
for: (a) a bare gold
1
electrode; and (b) a gold electrode coated with a film of poly-[CuL ]
[28] P. Day, N.J. Sanders, J. Chem. Soc. A (1967) 1530.
[29] A.R. Amundsen, J. Whelan, B. Bosnich, J. Am. Chem. Soc. 99
(1977) 6730.
2
−
9
−2
(~=4×10
mol cm ) both in 0.1 M aqueous H SO solution
2 4
saturated with oxygen.