Angew. Chem. Int. Ed. http://doi.org/f2b582 (2013)
The double helical structure of DNA is often a source of inspiration for synthetic supramolecular chemists, and researchers have previously created double helices made from strands of two distinct but complementary polymers that are held together through non-covalent interactions. Eiji Yashima and colleagues at Nagoya University have now self-assembled double helices from two strands of the same polymer.
The polymer has an m-terphenyl-based backbone; the m-terphenyl group consists of three benzene groups connected in a crescent shape by single carbon–carbon bonds. A carboxylic acid recognition group is attached to the central benzene and drives the self-assembly process through the formation of hydrogen bonds between the carboxylic acid groups on two polymer strands.
The homopolymer system does not have a preferred helicity (the crystal structure is racemic), but amplification of helical chirality can be achieved in solution by adding a chiral molecule. In particular, Yashima and colleagues show that if a chiral amine sits between the two strands to form a sandwiched structure, it can transfer the chiral information to the strands by inducing aggregation of the double helix into a preferred handedness. The self-assembly mechanism is driven by an acid–base recognition motif between the amine and the carboxylic groups of the two strands.