Room-Temperature Spin-Transition Iron Compounds

Spin transition complexes are an interesting class of materials exhibiting molecular bistability with potential applications in nanotechnological devices as memory storage units, sensors or displays. Since the discovery of the spin transition phenomenon in tris(N,Ndialkyldithiocarbamato) iron(III) complexes, numerous investigations have been devoted to this field of molecular magnetism. The spin transition phenomenon is probably the most spectacular example of bistability in molecular chemistry. However, it is a challenge to obtain spin transition materials when working under ambient conditions (eg. room temperature and pressure), which would be highly advantageous for potential applications. So far, only some Fe(II) and Fe(III) molecular systems have shown temperature-induced spin transitions around and even above room temperature. Within this review, we discuss the characteristics of this class of bistable compounds in detail and we try to draw more general conclusions regarding the integration, implementation and application of spin transition compounds as switching elements in hybrid molecular devices.