Ice-ray pentagonal packing of pseudo-fivefold helices
While fivefold point symmetry is common in nature, fivefold spatial symmetry is seldom observed. Regular pentagons cannot tile a plane without leaving voids, and even the densest “ice-ray” packing is exceptionally rare. Fivefold helices are equally elusive. We report a small molecule that self-assembles into hydrogen-bonded pseudo-fivefold helices and adopts an ice-ray pentagonal packing motif over crystallographic length scales using peripheral disorder that partially occupies regions that would otherwise be void in an ideal pentagonal tessellation. The resulting structure exhibits weak and nondirectional interhelical interactions within the ( bc ) plane and comparatively strong and directional intrahelical hydrogen bonding along the a axis. This structural anisotropy gives rise to single crystals with large aspect ratios and distinct mechanical behavior. This realization of two rare structural motifs within a single crystal shows the capability of simple organic molecules to form complex structures and highlights an untapped potential for symmetry engineering in molecular solids through the interplay of intermolecular interactions with pronounced differences in strength and directionality.
Authors
- Pancě Naumov (ORCID: https://orcid.org/0000-0003-2416-6569)
- Lida Aeindartehran (ORCID: https://orcid.org/0000-0001-7592-1363)
- Anibal Javier Ramirez-Cuesta (ORCID: https://orcid.org/0000-0003-1231-0068)
- Yongqiang Q. Cheng (ORCID: https://orcid.org/0000-0002-3263-4812)
- Jin S. Zhang (ORCID: https://orcid.org/0000-0002-1936-7780)
- J. Hu (ORCID: https://orcid.org/0009-0009-5026-6214)
- Ibrahim Tahir (ORCID: https://orcid.org/0000-0001-9231-9809)
- Nilanjan Seal (ORCID: https://orcid.org/0000-0001-5822-8831)
- W. Stoll (ORCID: https://orcid.org/0000-0002-9418-6445)
- Michael T. Ruggiero (ORCID: https://orcid.org/0000-0003-1848-2565)
- Murillo Longo Martins (ORCID: https://orcid.org/0000-0002-3883-9114)
- Alejandro Santis Alvarez (ORCID: https://orcid.org/0000-0003-2238-9291)
- Tomče Runčevski (ORCID: https://orcid.org/0000-0003-0886-8464)
- Ejaz Ahmed (ORCID: https://orcid.org/0000-0002-3676-2950)
- Daniel K. Unruh (ORCID: https://orcid.org/0000-0002-2594-5786)
- Luke J. Kwan (ORCID: https://orcid.org/0009-0002-3535-4629)
- Maria Petrov (ORCID: https://orcid.org/0009-0009-7416-3674)
- Anja Milenkova (ORCID: https://orcid.org/0009-0008-0147-0780)
- Nathan Taton
- Robert E. Dinnebier
Institutions
- New York University Abu Dhabi (AE)
- University of Iowa (US)
- Oak Ridge National Laboratory (US)
- Macedonian Academy of Sciences and Arts (MK)
- Southern Methodist University (US)
- University of Strathclyde (GB)
- Max Planck Institute for Solid State Research (DE)
- Sustainability Institute (ZA)
- University of Rochester (US)
- New York University (US)
- Texas A&M University (US)
Publication Details
- Journal
- Proceedings of the National Academy of Sciences
- Published
- 2026-10-14
- DOI
- https://doi.org/10.1073/pnas.2608878123
- Primary Topic
- Quasicrystal Structures and Properties
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Welch Foundation
- Research Institute Centers, New York University Abu Dhabi