Ice-ray pentagonal packing of pseudo-fivefold helices.

A small molecule forms an ice-ray pentagonal packing motif with pseudo-fivefold helices, demonstrating rare fivefold symmetry at crystallographic length scales.

• Why it matters: Fivefold symmetry is uncommon in nature and difficult to achieve in molecular assemblies, limiting understanding and potential applications of such complex structures.
• What they did: The researchers synthesized a small molecule that self-assembles into hydrogen-bonded pseudo-fivefold helices, adopting an ice-ray pentagonal packing with peripheral disorder over crystallographic scales.
• The result: This structure exhibits weak, nondirectional interhelical interactions in the (bc) plane and strong, directional intrahelical hydrogen bonds along the a axis, enabling large aspect ratio crystals with unique mechanical properties.