Non-covalent synthesis of organic nanostructures
This review describes the synthesis, characterization and functionalization of hydrogen bonded, box-like assemblies. These assemblies are formed upon mixing bismelamine calix[4]arenes with a complementary barbiturate in apolar solvents. Various techniques for the characterization have been used, like 'H NMR spectroscopy, X-ray crystallography and a novel MALDI-TOF MS technique. The use of cyanurates instead of barbiturates results in the formation of three conformational isomers. The ratio in which these assemblies are formed depends on the N-substituent of the cyanurate. Substituting the bismelamine calix[4]arenes with a variety of functional groups enables the formation of assemblies in which functionalities are gathered around a box-like cavity. Mixing these homomeric assemblies creates a dynamic combinatorial library of heteromeric assemblies.