SELF-ASSEMBLING DENDRIMERS

Hydrogen bond-mediated self-assembly is a powerful strategy for genera ting large structures from smaller subunits. The synthesis of molecule s containing two isophthalic acid units covalently attached to a rigid aromatic spacer is described. By normal pairing of carboxylic acids i nto hydrogen-bonded dimers, these molecules self-assemble in organic s olvents to form either a series of linear aggregates or a cyclic hexam er. These molecules were linked to the core of a family of polyether d endrimers, which caused the hexamer to be formed preferentially. The s tability of the hexamer depended on the generation number of the dendr imer. The largest of these hydrogen-bonded macromolecular assemblies i s roughly disk-shaped with a 9-nanometer diameter and a 2-nanometer th ickness. Its size and molecular mass (34,000 daltons) are comparable t o that of small proteins.