Supramolecular catalysts featuring crown ethers as recognition units
In its minimal expression, a supramolecular catalyst that acts on a single bound substrate consists of (i) a binding unit that is complementary to a non-reacting part of the substrate, (ii) a reactive unit capable of catalyzing the reaction of the bound substrate, and (iii) a spacer connecting the two units in a geometry suitable for productive binding. When binding of two or more species is wanted, the number of binding units increases accordingly.