Metal Complexes as Chelates II
Binuclear complexes containing similar and dissimilar metal atoms
A new series of oxygen-bridged complexes is reported with special emphasis on copper(II). Most of these complexes can be shown to be discrete dimeric molecules. Both homo- and heteronuclear dimers can be prepared in a large number of cases, by forming a complex of metal M with a tetradentate salicylaldimine, L, and, in turn, using this complex itself as a ligand. The latter (ML) then acts as a bidentate in complexing with a metal halide, MX 2 or M′X 2, to which it coordinates through its two phenolic oxygens. The Schiff base complexes used here as ligands (“complex ligands”) are tetradentate Schiff base complexes of copper(II) and nickel(II). The former are normal paramagnetics, in contradistinction to reports of anomalous magnetic moments, and the latter are well known to be diamagnetic. The binuclear complexes are generally considerably less soluble in organic solvents than the complex ligands, so that many different complexes can be formed by direct reaction in saturated solutions. Both the complex ligands and the binuclear complexes are nonionic in nitrobenzene. All of the homonuclear complexes of copper(II) show antiferromagnetic interactions, which can readily be explained in terms of the well-established “Bleany-Bowers” theory. Heteronuclear complexes so far prepared involving copper(II) with other paramagnetic and diamagnetic metals and nickel(II) with other paramagnetic metals are simple paramagnetics and their magnetic properties are in accord with the Curie-Weiss law, between 80 and 400°K, with relatively small Weiss constants.
S. J. Gruber et al., "Metal Complexes as Chelates II," Inorganic Chemistry, American Chemical Society (ACS), Jan 1968.
The definitive version is available at http://dx.doi.org/10.1021/ic50060a020
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© 1968 American Chemical Society (ACS), All rights reserved.