Exchange-coupled cobalt(II) dimer with unusual magnetic circular dichroism saturation behavior.
The exchange-coupled complex [Co(2)(mu-H(2)O)(mu-OAc)(2)(OAc)(2)(tmen)(2)] (OAc = CH(3)COO(-) acetato; tmen = N,N,N',N'-tetramethylenediamine) has been studied by magnetic circular dichroism (MCD) spectroscopy and magnetization measurements. A peculiar behavior of the MCD spectra was observed with a change in the magnetic field. The intensity of particular lines initially increases, then decreases with an increase in the magnetic field strength, disappears with a further field increase, and appears again with the opposite sign. This behavior was explained by the overlap of the electronic transitions at different but near wavelengths. The obtained MCD magnetization curves, together with magnetization obtained by a SQUID magnetometer, are well reproduced using the Hamiltonian, which takes into account an orbital magnetic moment.
Ostrovsky
S
S
Eduard-Zintl-Institute of Inorganic and Physical Chemistry, Darmstadt University of Technology, Petersenstrasse 20, 64287 Darmstadt, Germany.
Tomkowicz
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Z
Haase
W
W