Molecule- and polymer-based magnets, a new frontier

Molecule- and polymer-based magnets prepared by relatively low temperature organic synthetic methodologies are of increasing interest in materials research. The three distinct models enabling the design of new molecule- and polymer-based magnetic materials are given. Bulk ferromagnetic behavior with hysteresis was first observed below the critical (Curie) temperature, T-c, of 4.8 K for [Fe-III(C(5)Me(5))(2)](.+) [TCNE](.-) (Me = methyl; TCNE = tetracyanoethylene). Since then, many new classes of molecule- and polymer-based magnets have been discovered, including those with T-c above room temperature, such as V(TCNE)(x) . y(CH2Cl2). The important roles of spin and spatial anisotropy and also disorder are illustrated. The anticipated properties of such molecule- and polymer-based magnetic materials may enable their use in future generations of electronic, magnetic and/or photonic/photronic devices ranging from information storage and magnetic imaging to static and low frequency magnetic shielding and magnetic induction.