Systematic design of amide- and urea-type gelators with tailored properties.

The formation of gels by structurally highly diverse low molecular weight organic molecules is paradigmatically a supramolecular phenomenon. It is based on the self-assembly of certain organic molecules and involves highly specific noncovalent intermolecular interactions, in particular those inducing predominantly unidirectional aggregation. In this chapter, the design of low molecular weight gelators that incorporate single or multiple amide units as intermolecular hydrogen-bonding functionalities and methods of their preparation are given. Many efficient gelators of organic solvents and water could be prepared by the structural combination of amidic, carbamate, urea, or oxalamide groups and long aliphatic chains or aromatic groups with a large surface. The numerous potential applications in slow drug-delivery systems, the fabrication of templated materials, and in sensing devices are also discussed.