Reversible single-crystal-to-single-crystal transformations in coordination compounds induced by external stimuli

This review discusses recent advanced literature reported on crystalline Coordination Compounds with emphasis in Coordination Polymers (CPs) involving reversibility in single-crystal to single-crystal transformations (SCSC). The reversibility, characteristic of certain processes which can be reversed and restored to its initial state, can be a very important factor, but at the same time difficult to achieve without losing partially, or completely, the crystallinity of some molecular-based materials. Nevertheless, in recent times some outstanding examples of reversible SCSC transformation appear in the literature. These examples will be described, and the observed physicochemical properties variation (i.e. changes in dimensionality, polymerization, polymorphism, changes in colour and texture, etc.) due to external stimuli (mainly temperature, loss/uptake of solvent vapours) will be evaluated. Such alterations in the properties of these compounds mean that they can be used in various applications such as sensors, molecular machines and selective compounds storage, among others.