Single-crystal EPR and theoretical investigations on the 'paramagnetic impurity' (n-B4N)(2)[Cu(mnt)(2)] built upon preparation of the antiferromagnetically coupled binuclear (n-Bu4N)(2)[(mnt)Cu(tto)Cu(mnt)]

The paramagnetic Cu-II impurity observed by EPR in all prepared samples of the binuclear antiferromagnetically coupled (n-Bu4N)(2)[(mnt)Cu(tto)Cu(mnt) ] (mnt = 1,2-dicyanoethene-1,2dithiolate; tto = tetrathiooxalate) has been identified to be [Cu(mnt)(2)](2 -). The experimental data as well as the re sults from density functional theory (DFT) calculations are used to charact erize the spin-density distribution in the mononuclear Cu-II complex. (C) 2 000 Elsevier Science S.A. All rights reserved.