Researchers at Kanazawa University synthesized helical ladder polymers with a well-defined cyclic repeating unit and one-handed helical geometry, as they reported in the Journal of the American Chemical Society.
Ladder polymers—molecules made of adjacent rings sharing two or more atoms—are challenging to synthesize, because they require highly selective, quantitative reactions to avoid the formation of branching structures or of interruptions in the ring sequence in the polymer chain. Moreover, most existing strategies for the synthesis of ladder polymers suffer from severe limitations in terms of selectivity and quantitativity. Another important type of molecules are molecules with a helical structure (such as DNA and proteins), which play an important role in molecular recognition and catalysis. Thus, the fabrication of molecules that possess both a ladder and a helical structure could open up new applications of polymeric materials.