ABSTRACT
In the 1960s the concept of an “enthalpy-entropy compensation relationship” was proposed by Leffler [1]. This concept was very helpful for obtaining insights into a number of thermodynamic data for association and kinetic processes. However, this also implies that high selectivity and high activity cannot appear in one reaction series. Then, how can we create such an exceptional system with high selectivity and high activity that deviate from the enthalpy-entropy compensation relationship? This was the starting point of our chemistry. This query becomes especially important when we mimic the high selectivity and the high activity of enzymes in the field of biomimetic chemistry. The break through was achieved when we realized that as long as one association process or one kinetic process is treated independently, it is restricted by the relation-
ship whereas if two or more systems are coupled reversibly, one may find an exceptional process diverted from the relationship through “switching” between the systems. The original concept has enabled us to create a number of new ion and molecule recognition systems that are combined with switch-functionalized and molecular-assembly systems. In particular, we have noticed that light is a very promising trigger to provide switching functions for functional molecular systems (Fig. 1).
