Energetically Demanding Transport in a Supramolecular Assembly

A challenge
in contemporary chemistry is the realization of artificial
molecular machines that can perform work in solution on their environments.
Here, we report on the design and production of a supramolecular flashing
energy ratchet capable of processing chemical fuel generated by redox
changes to drive a ring in one direction relative to a dumbbell toward
an energetically uphill state. The kinetics of the reaction pathway
juxtapose a low energy [2]­pseudorotaxane that forms under equilibrium
conditions with a high energy, metastable [2]­pseudorotaxane which
resides away from equilibrium.