Self-assembly of non-biological polymeric strands undergoing enforced helical self-organization

The polycondensation of a dihydrazino-pyrimidine (5 and 6) with a pyrimidine-dicarbaldehyde (7 and 8b) provides an efficent access to helical polymeric strands based on the formation of hydrazone connections between the pyrimidine groups. The folding into a helical structure is enforced by the helicity codon defined by the (hydrazone-pyrimidine) sequence. ne polymers obtained have been characterized by mass spectrometry, indicating molecular weights up to ca. 12000 Da. Electronic spectra display specific absorption and emission features. These helical polymers present a core diameter of ca. 20 Angstrom, a pitch of 3.5 Angstrom, and, for a molecular weight around 9000 Da, a height of ca. 42 A with 12 turns. The self-assembled helical polymers obtained represent stable frameworks for the lateral attachment of functional residues in a helical disposition. Such entities may possess a range of novel chemical as well as biological properties.