Multifunctional pentazole materials: Preparation, structure, and properties

Abstract

The newest species of polynitrogen compounds, pentazolate anion (cycloN₅⁻), has garnered significant interest from its successful preparation through chemical methods in 2017. This carbon- and hydrogen-free five-membered ring exhibits extremely high energy properties and unique structural characteristics. As the novel polynitrogen compound after N₂, N₃⁻, and N₅⁺, this substance can release significant energy during decomposition, only producing environmentally friendly N₂. Five equivalent nitrogen atoms form similar binding sites, constructing diverse and colorful pentazolate compounds and derivatives. This review focuses on pentazolate compounds as energetic compounds, multifunctional materials with relevant theoretical simulations and experimental syntheses. The following items are included in this review: (1) achieving purification and large-scale production of pentazolate anion through the use of an iron single-atom catalyst; (2) a variety of metal pentazolate frameworks with zeolite-like structures and a series of energetic coordination polymers that have the potential to be used as explosives; (3) nonmetallic materials with high density, heat of formation, and energy performance, and complexes increasing decomposition temperature to improve physicochemical properties; (4) thermal decomposition mechanism and stabilization strategy dominated by hydration and hydrogen bonding interactions; (5) pentazolate derivatives represented by HN₅, FN₅, NH₂N₅, (CH₃)₂NCHN-N₅, N₈, and N₁₀; and (6) considerations for future theoretical and experimental explorations. This review introduces a systematic summary and apprehending of pentazolate compounds, aiming to explore their potential as next-generation high-energy and environmentally friendly energetic compounds and applications of multifunctional materials in various fields.