MAGNETIC COUPLING IN END-ON AZIDO-BRIDGED TRANSITION-METAL COMPLEXES - A DENSITY-FUNCTIONAL STUDY

The effect of structural parameters on the exchange coupling constant of the title complexes of Cu(II), Ni(II), and Mn(II) is studied by mea ns of density functional calculations on model compounds. The studied parameters are the bridging M-N-M angle, the M-N bond distance, and th e out-of-plane shift of the azido bridge. The model compounds in their most stable geometry, as well as some full molecules in their experim ental structures, appear in a high-spin ground state showing ferromagn etic coupling in all cases. The atomic spin density distributions of t he model compounds are interpreted as resulting from the interplay bet ween electron delocalization and spin polarization.