π-Stacking Stopper-Macrocycle Stabilized Dynamically Interlocked [2]Rotaxanes

The synthesis of mechanically interlocked molecules is valuable due to their unique topologies. With pi-stacking intercomponent interaction, e.g., phenanthroline and anthracene, novel [2]rotaxanes have been synthesized by dynamic imine clipping reaction. Their X-ray crystal structures indicate the pi-stackings between the anthracene moiety (stopper) on the thread and the (hetero)aromatic rings at the macrocycle of the rotaxanes. Moreover, the length of glycol chains affects the extra pi-stacking intercomponent interactions between the phenyl groups and the dimethoxy phenyl groups on the thread. Dynamic combinatorial library has shown at best 84% distribution of anthracene-threaded phenanthroline-based rotaxane, coinciding with the crystallography in that the additional pi-stacking intercomponent interactions could increase the thermodynamic stability and selectivity of the rotaxanes.

Automated summary

The synthesis of mechanically interlocked molecules with unique topologies through pi-stacking intercomponent interactions has been studied. The length of glycol chains affects the stability and selectivity of the rotaxanes. The additional pi-stacking intercomponent interactions can increase the thermodynamic stability and selectivity of the rotaxanes, as shown by dynamic combinatorial library.