Spin-state switching in Fe(II) helicates and cages

Despite the intense interest in helicate and cage supramolecular architectures, only a small fraction of these are known to switch their spin-state in response to a stimulus, such as temperature and light. However, these have recently emerged as a promising new class of spin-crossover materials and although there are still relatively few examples, it is an active area of research. This review discusses the lessons learned and challenges associated with the design and study of spin-crossover helicates and cages before highlighting new developments in the field. [GRAPHICS] .