Tetracyanoethylene-based organic magnets

Several classes of organic magnets based upon the tetracyanoethenide radical anion, [TCNE](.-), either unbound, (u), and (u4) bonded to zero, two and four metal sites have been reported. The putative (u4) bonded V(TCNE)x room temperature magnet has been extended to include M(TCNE)x(M = Mn, Fe, Co, Ni) magnets. M for this class of magnets is assigned to be in the divalent oxidation state. A (o-[TCNE](22-) dimer intermediate has been isolated. The intrachain magnetic coupling for the 1-D coordination polymers having [TCNE](.-u)-bridge bonded to [MnIIIporphyrins]+ is discussed in the context of a structure-function correlation arising from the dihedral angle between the [MnIIITPP]+'s MnN4 and [TCNE](.-) mean planes and the magnitude of magnetic coupling. This correlation is ascribed to the increasing importance of the (o-MnIII dz2/[TCNE](.-pz overlap with decreasing dihedral angle.