Abstract
The tetranuclear Cu4OBrnCl(6-n)L4 complexes, where L = 3-methylpyridine (3-Mepy), 4-methylpyridine (4-Mepy) and n=0–6 with trigonal bipyramidal coordination of copper(II) were prepared and their infrared and electronic absorption spectra as well as cyclic voltammograms in nitromethane solutions were measured. The polyhedra in Cu4OBrnCl(6−n) (3-Mepy)4 molecules are less distorted comparing with those of 4-Mepy analogues as indicated by infrared Cu4O absorptions, far infrared Cu—Br, Cu—Cl, and Cu—N absorptions, d—d bands in electronic spectra and potentials, measured by cyclic voltammetry. The 3-Mepy complexes exhibit strong single infrared Cu4O absorptions, while for related 4-Mepy complexes doubly split Cu4O bands were observed. Two strongly overlapped d—d bands in electronic absorption spectra of the 3-and 4-Mepy complexes in nitromethane were resolved by Gaussian fitting. The 4-Mepy ligand produces slightly stronger ligand field than its 3-Mepy analogue. The maxima of high-energy d—d bands are in a linear correlation with the number of bromide ligands. The correlations for corresponding low-energy bands are considerably deviated from linearity. The halfwave potentials of the complexes in nitromethane correlate with both the number of bromides and the data of electronic absorption spectra suggesting that the reducing electron at the electrode process enters the half-filled d z 2 orbital of the copper(II) atom. The origin of a difference between the 3-and 4-Mepy complexes in their spectral and electrochemical properties is also discussed.
Similar content being viewed by others
References
tom Dieck, H., Inorg. Chim. Acta 7, 397 (1973).
Gill, N. S. and Sterns, M., Inorg. Chem. 9, 1619 (1970).
Jorík, V., Koman, M., Makáňová, D., Mikloš, D., Broškovičová, A., and Ondrejovič, G., Polyhedron 15, 3129 (1996).
Ondrejovič, G. and Kotočová, A., Chem. Pap. 59, 166 (2005).
tom Dieck, H. and Brehm, H. P., Chem. Ber. 102, 3577 (1969).
Greenwood, N. N. and Wade, K., J. Chem. Soc. 1960, 1130.
Spinner, E., J. Chem. Soc. 1963, 3860.
Ondrejovič, G. and Kotočová, A., Chem. Pap. 55, 221 (2001).
Wong, P. T. T. and Brewer, D. G., Can. J. Chem. 46, 139 (1968).
Grazinska, E. and Wojciechowski, W., Pol. J. Chem. 58, 977 (1984).
Kožíšková, Z., Kožíšek, J., and Kabešová, M., Polyhedron 9, 1029 (1990).
Kabešová, M. and Kožíšková, Z., Collect. Czech. Chem. Commun. 54, 1800 (1989).
Marsh, W. E., Hatfield, W. E., and Hodgson, D. J., Inorg. Chem. 21, 2679 (1982).
Van Ooijen, J. A. C. and Reedijk, J., Inorg. Chim. Acta 25, 131 (1977).
Kilbourn, B. T. and Dunitz, J. D., Inorg. Chim. Acta 1, 209 (1967).
Swank, D. D., Nielson, D. O., and Wilett, R. D., Inorg. Chim. Acta 7, 91 (1973).
Hathaway, B. J. and Billing, D. E., Coord. Chem. Rev. 5, 143 (1970).
Nicholson, R. S. and Shain, I., Anal. Chem. 36, 706 (1964).
Workie, B., Dubé, C. E., Aksu, L., Kounaves, S. P., Robat, A., Jr., and Davies, G., J. Chem. Soc., Dalton Trans. 1997, 1739.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ondrejovič, G., Kotočová, A. Spectral and electrochemical study of coordination molecules Cu4OX6L4: 3-Methylpyridine and 4-Methylpyridine Cu4OBrnCl(6−n)L4 complexes. Chem. Pap. 60, 10–21 (2006). https://doi.org/10.2478/s11696-006-0003-2
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.2478/s11696-006-0003-2