Do pi-pi Stacking Interactions Really Play a Role in the Magnetic Coupling Mechanisms of [Cu-2(mu(2)-CH3COO)(2)L-2(H2O)(2)](n+) (L = heterocyclic base, n=0, 2) Complexes? An ab initio Inspection

The magnetic properties of two bis-acetate binuclear copper(II) complexes, namely [Cu-2(mu(2)-CH3COO)(2)(bpydiol-H)(2)(H2O)(2)] (bpydiol-H = mono deprotonated 2,2'-bipyridine-3,3'-diol) and [Cu-2(mu(2)-CH3COO)(2)(phen)(2)(H2O)(2)](2+) (phen = 1,10-phenantroline), is revisited using ab initio wave function-based calculations (CASSCF, DDCI). Thanks to an analysis of the magnetic exchange coupling based on localized orbitals, it is shown that, unlike stated in the original work [C. Hou et al. Dalton Trans. 2008, 5970], pi-pi interactions do not contribute to the overall antiferromagnetism character of these complexes.