Following a recently reported synthesis of linearly halide-bridged Cu(II) complexes [Inorg. Chem. 2012, 51,
7966-7968] characterized by strong antiferromagnetic exchange couplings (J), we applied Difference Dedicated
Configuration Interaction (DDCI) and Broken-Symmetry Density Functional Theory (BS-DFT) approaches in order to
analyze theoretically the trend observed, in which the decreasing electronegativity of the central halide induces an
exacerbed magnetic coupling. The importance of the magnetic orbitals in DDCI calculations is acknowledged. The use of
reduced molecular models is shown to lead to significant differences in J, in the case of chloride and bromide bridges.
Finally, the BS-DFT decomposition of J in its main physical contributions confirms the importance of the kinetic
exchange mediated by the halide bridge, but also points towards an increasing core polarization contribution when going
from fluoride to bromide.
Aix-Marseille Université, CNRS, Institut de Chimie Radicalaire, 13397 Marseille Cedex 20, France.