THE DESIGN OF ARTIFICIAL RECEPTORS FOR COMPLEXATION AND CONTROLLED AGGREGATION

Simple synthetic receptors have been developed that function via directed hydrogen bonding interactions in highly competitive solvents. Strong binding of this type in polar solvents may be due to a number of factor including favourable secondary hydrogen bonding interactions between the carboxylate and urea, the use of charged H-bond acceptors, an inefficient solvation of the closely spaced H-bond donor sites in the urea, and an entropically favourable release of solvent and/or counterion molecules on complex formation. We also demonstrate that these types of interactions can be used to induce, both in solution and the solid state, discrete 2+2 aggregates stabilized by a network of hydrogen bonds.