Helical self-assembled polymers from cooperative stacking of hydrogen-bonded pairs

The double helix of DNA epitomizes this molecule's ability to self-assemble in aqueous solutions into a complex chiral structure using hydrogen bondin g and hydrophobic interactions. Noncovalently interacting molecules in orga nic solvents are used to design systems that similarly form controlled arch itectures(1-7). Peripheral chiral centres in assemblies(8,9) and chiral sid e chains attached to a polymer backbone(10,11) have been shown to induce ch irality at the supramolecular level, and highly ordered structures stable i n water are also known(12-15). However, it remains difficult to rationally exploit non-covalent interactions for the formation of chiral assemblies th at are stable in water, where solvent molecules can compete effectively for hydrogen bonds. Here we describe a general strategy for the design of func tionalized monomer units and their association in either water or alkanes i nto non-covalently linked polymeric structures with controlled helicity and chain length. The monomers consist of bifunctionalized ureidotriazine unit s connected by a spacer and carrying solubilizing chains at the periphery. This design allows for dimerization through self-complementary quadruple hy drogen bonding between the units and solvophobically induced stacking of th e dimers into columnar polymeric architectures, whose structure and helicit y can be adjusted by tuning the nature of the solubilizing side chains.