Abstract
On the basis of a detailed quantum-chemical (ab initio and INDO) analysis, it has been shown that the experimentally observed ferromagnetic properties of axially coordinated bischelating complexes of Cu(II) with nitroxyl ligands (in contrast to the antiferromagnetic properties of equatorially coordinated complexes of the same type) cannot be explained in the framework of the concept of direct exchange interaction. An alternative (delocalization) mechanism of ferromagnetic exchange interaction has been proposed. This mechanism is due to slight delocalization (p ≃ 10−2-10−3) of the unpaired electron from the π*-antibonding MO of nitroxyl radicals onto the valence AO (mainly on the 3dz2 AO) of the central paramagnetic Cu(II) ions. The predicted values of the exchange interaction in a series of axially coordinated complexes of Cu(II) are in good agreement with the experimental data obtained from magnetic measurements.
Original language | English |
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Pages (from-to) | 4118-4121 |
Number of pages | 4 |
Journal | Inorganic Chemistry |
Volume | 31 |
Issue number | 20 |
DOIs | |
State | Published - 1992 |