Exchange interaction in oxygen-bridged dimers of copper(II) with aromatic N-oxides : Part 2. Effects of the bridge angle and of aromatic-ring substituents

Abstract

The method based on the Dirac—Van Vleck—Serber permutation degeneracy model described in Part 1 of this work is used for further examination of the exchange interaction in oxygen-bridged dimers of copper(II) with aromatic N-oxides. The bridge angle at the oxygen is found to have a large effect on the values of the exchange integral J. But substituents on the aromatic ring, which certainly affect the structural data, do not significantly affect J despite their modifying effect on the effective charge of oxygen and on (one-electron) orbital energies. Finally a unique correlation between a number of INDO-calculated substituent parameters (electron populations of oxygen and orbital energies) and the experimental J values cannot be traced; this may be attributed to the important part played by intra- and inter-dimer interactions not explicitly considered in the calculations.