Pressure in Coordination Chemistry II
Antiferromagnetic complexes of copper(II)
The effect of high pressure (1-3000 atm) on the magnetic properties of binuclear carboxylate complexes of copper(II), all of which exhibit pairwise antiferromagnetic interactions, is found to be surprisingly small, when the measurements are made on solutions in aprotic solvents or on the solids mulled in inert media. This indicates that there is little reduction in volume in going from the “triplet state” dimer (with one unpaired electron per copper) to the “singlet state” dimer (diamagnetic). The polymeric copper(II) oxalate behaves similarly. This result is best explained in terms of a weak copper-copper interaction, in the form of a δ bond or a superexchange mechanism. In solutions containing “structure-breaking” solvents, such as ethanol or pyridine, there is an increase in magnetic susceptibility with increasing pressure, which is attributed to the dissociation of the bimolecular complexes.
A. H. Ewald and E. Sinn, "Pressure in Coordination Chemistry II," Inorganic Chemistry, American Chemical Society (ACS), Jan 1969.
The definitive version is available at http://dx.doi.org/10.1021/ic50073a024
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© 1969 American Chemical Society (ACS), All rights reserved.