New chelating nitroxide free radical ligands for heterospin-magnetic engineering

Polychelating nitroxide ligands derived from N-methylethylenediamine and pi perazine have been prepared by reactions of 2-bromomethyl nitronyl nitroxid e with the corresponding polyamines. Two of these ligands have been structu rally and magnetically characterized, along with some of their transition m etal complexes, the magnetic properties of which are compared to those of p reviously reported related species. In particular, the properties of a nick el(II) derivative of a pentadentate tris(nitroxide), the ground spin-state of which is a quadruplet, are discussed in detail.