Ab initio calculations of the magnetic exchange coupling in sulfur-bridged binuclear Ni(II) complexes

The geometry dependence of the exchange integrals and the total energies of sulfur-bridged complexes of the types L₅NiSNiL₅, L₄NiS₂NiL₄, and L₃NiS₃NiL₃ is studied by quantum chemical ab initio methods. The linear monobridged complex is antiferromagnetic, the bi- and triply-bridged complexes are ferromagnetic for NiSNi angles between 85° and 100° and antiferromagnetic for smaller and larger angles. The superexchange mechanism is analyzed, and a comparison with oxygen-bridged complexes and experimental data is performed. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 65: 633–641, 1997