New Chelating Nitroxide Free Radical Ligands For Heterospin-Magnetic Engineering

Polychelating nitroxide ligands derived from N-methyl-ethylenediamine and piperazine have been prepared by reactions of 2bromomethyl nitronyl nitroxide with the corresponding polyamines. Two of these ligands have been structurally and magnetically characterized, along with some of their transition metal complexes, the magnetic properties of which are compared to those of previously reported related species. In particular, the properties of a nickel(II) derivative of a pentadentate tris(nitroxide), the ground spin-state of which is a quadruplet, are discussed in detail.