Magnetic properties of layered complexes [M(hfac)(2)](3)(R)(2), M = Mn(II)and Cu(II), with trisnitroxide radicals having various metal-radical exchange interactions

A series of new layered 2D-network complexes [M(hfac)(2)](3)(R-Delta)2 of M = Mn(II) and Cu(II) with trisnitroxide radicals R-Delta has been prepared and the magnetic properties were studied. Each triradical R-Delta has a qua rtet ground state and contributes not only to the formation of extended str uctures but essentially to the overall magnetism. Several exchange interact ions, between M and nitroxide and intraradical nitroxide-nitroxide interact ions, are responsible for the development of the characteristic magnetic pr operties in these heterospin systems. Depending on the nature of the interl ayer interactions, they show either ferro/ferrimagnetic or antiferromagneti c long range order. The hierarchy of the different exchange interactions is established and the Mn-nitroxide and Cu-nitroxide exchange integrals are e valuated from the analysis of the temperature dependence of the paramagneti c susceptibility. With increasing intraradical exchange interaction, the co mplexes exhibit more pronounced 2D behaviour.