Organic radical magnetic materials

Organic radical magnetic materials lacking directional crystal assembly functionality 130... 

Although many naturally occurring and designed materials are magnetic due to incorporation of paramagnetic ions or metal atoms, organic-based magnets are composed of molecules or (in the case of polymers) monomeric repeat units. Each molecule must have net unpaired electron spin density. Several example radical spin units are shown in Scheme 1. The unpaired spin may be... 

We now turn to considering exchange linkage between spin units in a more general fashion, as a transition from organic radical spin units to organic magnetic materials. 

A particularly promising variant of organic magnetic materials design is the pairing of different radicals having complementary crystal assembly units. In... 

This chapter will show that only atoms with partially filled shells (i.e. atoms with unpaired electrons) can possess a net magnetic moment in the absence of an external field. Since main group p block) elements have atoms with filled d subshells and tend to form compounds with other p-block elements that result in filled p subshells in accordance with the octet rule, the vast majority of magnetic materials have historically contained transition metal atoms with partially filled d subshells. Nevertheless, some pure organic compounds with free radicals have been found to exhibit ferromagnetic intermolecular interactions, albeit at very low temperamres (several Kelvins). 

Benelli, C. and Gatteschi, D. (2002) Magnetism of lanthanides in molecular materials widi transition-metal ions and organic radicals. Chemical Reviews, 102, 2369-2387. 

Benelli, C., Caneschi, A., Gatteschi, D., and Sessoh, R. (1993) Magnetic properties and phase transitions in molecular based materials containing rare earth ions and organic radicals (invited). Journal of Applied Physics, 73, 5333-5337. 

---