An important aspect of molecular engineering is the property directed' synthesis of large molecules and molecular assemblies. Synthetic expertise has advanced to a state which allows the assembly of supramolecules containing thousands of atoms using a construction kit' of molecular building blocks. Expansion in the field is driven by the appearance of new building blocks and by an improved understanding of the rules for joining them in the design of nanometer-sized devices.
Another aspect is the transition from supramolecules to materials. At present no single molecule (however large)...