Mechanically Induced Opening–Closing Action of Binaphthyl Molecular Pliers: Digital Phase Transition versus Continuous Conformational Change

Reversible dynamic control of structure is a significant challenge in molecular nanotechnology. Previously, we have reported a mechanically induced continuous (analog) conformational variation in an amphiphilic binaphthyl, where closing of molecular pliers was achieved by compression of a molecular monolayer composed of these molecules at the air–water interface. In this work we report that a phase transition induced by an applied mechanical stress enables discontinuous digital (1/0) opening of simple binaphthyl molecular pliers. A lipid matrix at the air–water interface promotes the formation of quasi‐stable nanocrystals, in which binaphthyl molecules have an open transoid configuration. The crystallization/dissolution of quasi‐stable binaphthyl crystals with accompanying conformational change is reversible and repeatable. Open‐and‐shut case: Mechanical‐stimulus‐induced formation of quasi‐stable nanocrystals at the air–water interface enables conformational switching of a simple binaphthyl from cisoid to transoid (open to closed). The switching is reversible in an on/off manner, in contrast to a continuous conformational variation, and occurs only in mixed monolayers at the air–water interface, attesting to the importance of the medium for operation of this effect.