Spin crossover crystalline materials engineered via single-crystal-to-single-crystal transformations

Spin crossover continues to stimulate multidisciplinary research efforts worldwide as novel potential applications of its intrinsic molecular bistability property are envisaged. The challenge of mastering the switchable capability for its exploitation belongs largely to the realm of chemical design and synthesis. In this respect, single-crystal-to-single-crystal (SCSC) transformations as an effective engineering alternative method have attracted considerable attention in the design of specific spin crossover materials. However, spin state switching in a SCSC fashion between discrete molecular crystals has been limited, since crystals can hardly retain single crystallinity when they suffer from external stimuli. This highlight illustrates the latest crystalline materials engineered via SCSC transformations, with emphasis on the onset and progress of spin crossover in a crystal control.