Nonbonding Electron Delocalization Stabilizes the Flexible N8 Molecular Assembly

• Published in: The journal of physical chemistry letters 2024-02, Vol.15 (5), p.1507-1514
• Main Authors: Yao, Chuang, Dou, Kai-Le, Yang, Yezi, Li, Chongyang, Sun, Chang Q, Sun, Jian, He, Chunlin, Zhang, Lei, Pang, Siping
• Format: Article
• Language: English
• Subjects: Physical Insights into Materials and Molecular Properties
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.3c03285

Electron delocalization has an important impact on the physical properties of condensed materials. However, the L-electron delocalization in inorganic, especially nitrogen, compounds needs exploitation to improve the energy efficiency, safety, and environmental sustainability of high-energy-density materials (HEDMs). This Letter presents an intriguing N8 molecule, ingeniously utilizing nitrogen’s L-electron delocalization. The molecule, exhibiting a unique lollipop-shaped conformation, can fold at various angles with very low energy barriers, self-assembling into environmentally stable, all-nitrogen crystals. These crystals demonstrate unparalleled stability, high energy density, low mechanical sensitivity, and optimal electronic thermal conductivity, outperforming existing HEDMs. The remarkable properties of these designed materials are attributed to two distinct delocalized systems within nitrogen’s L-shell: π- and lone pair σ-electrons, which not only stabilize the molecular structure but also facilitate interconnected 3D networks of intermolecular nonbonding interactions. This work might pave the way to the experimental synthesis of environmentally stable all-nitrogen solids.