π–ring–hole bond around difluoroethyne: stabilization of hydrogen bonding cyclohexamer and dicyclohexamer of ammonia molecules.

The present paper displays new supramolecular structural forms of ammonia molecules. The computation reveals that two novel threading structures of C₂F₂·(NH₃)₆ and C₂F₂·(NH₃)₁₂ can be assembled between difluoroethyne and ammonia molecules, in which cyclohexamer (NH₃)₆ and dicyclohexamer (NH₃)₁₂ are constructed by robust N–H···N hydrogen bonds and stabilized all by π–ring–hole···N bonds as supporting spokes of annular structures. More interestingly, annular structures of NH₃ still maintain stability as C₂F₂ is removed. Additionally, the electronic properties and nature of the related noncovalent bonds are explored, which illuminate the important role of π–ring–hole bond for the stabilization of annular structures of NH₃. This study could provide valuable insights into chemistry of ammonia, new energy and astronomy aspects by single or multiple noncovalent interactions. Graphical abstract [ABSTRACT FROM AUTHOR]