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Proton Relaxation in Various Copper (II) Complexes and Determination of the Singlet-Triplet Separation

H. D. Jannek and W. Müller-Warmuth
Institut für Physikalische Chemie der Universität Münster
Z. Naturforsch. 35 a, 92-97 (1980);

[received December 3, 1979]

Proton spin-lattice relaxation rates have been measured at 30 MHz as a function of temperature for a large number of dimeric copper complexes with the ligands 8-hydroxyquinoIine, pyridine-N-oxide, methyl and dimethyl pyridine-N-oxide, and quinoline-N-oxide. Two carboxylates and adducts of several complexes with various solvents have also been studied. In contrast to some compounds with a normal magnetic behaviour, for most complexes a temperature dependent relaxation has been observed which agrees well with the concept of a weak antiferromagnetic interaction between the two Cu2+ ions. The singlet-triplet separations or exchange integrals have been determined.

I. Introduction