Nitrated-pyrazole-based energetic compounds have attracted wide publicity in the field of energetic materials (EMs) due to their high heat of formation, high density, tailored thermal stability, and detonation performance. Many nitrated-pyrazole-based energetic compounds have been developed to meet the increasing demands of high power, low sensitivity, and eco-friendly environment, and they have good applications in explosives, propellants, and pyrotechnics. Continuous and growing efforts have been committed to promote the rapid development of nitrated-pyrazole-based EMs in the last decade, especially through large amounts of Chinese research. Some of the ultimate aims of nitrated-pyrazole-based materials are to develop potential candidates of castable explosives, explore novel insensitive high energy materials, search for low cost synthesis strategies, high efficiency, and green environmental protection, and further widen the applications of EMs. This review article aims to present the recent processes in the synthesis and physical and explosive performances of the nitrated-pyrazole-based Ems, including monopyrazoles with nitro, bispyrazoles with nitro, nitropyrazolo[4,3-c]pyrazoles, and their derivatives, and to comb the development trend of these compounds. This review intends to prompt fresh concepts for designing prominent high-performance nitropyrazole-based EMs.

Cocrystals of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) and 2,4-dinitro-2,4-diazapentane (DNDAP) in a 2 : 1 molar ratio were prepared by both slow evaporation and spray drying methods. The structure of the cocrystals was characterized using single crystal X-ray diffraction and it showed evidence of hydrogen bonds between H_CL-20 and O_DNDAP to the primary stabilizing force in cocrystal formation. Infrared spectroscopy and powder X-ray diffraction analysis indicated that the polycrystalline product from the spray drying method is consistent with the single crystals from solution crystallization. DSC and TG tests revealed that the exothermic decomposition of the cocrystal occurs via two main continuous steps with peak maxima at 223.5 °C and 254.1 °C and largely increases the melting point of DNDAP by 129.9 °C. The cocrystal possesses high detonation velocity and detonation pressure (8997 m s⁻¹ and 37.5 GPa, respectively); meanwhile it features significantly reduced impact and friction sensitivities relative to those of CL-20. These results demonstrate that the CL-20/DNDAP cocrystal can be utilized as a promising ingredient in explosive applications.

Herein, the attachment energy (AE) model was employed to study the growth morphology of 3,4-bis(3-nitrofurazan-4-yl)furoxan (DNTF) under vacuum and solvent conditions by molecular dynamics simulation. The DNTF crystals were cultivated in H₂O/acetic acid (AcOH) and H₂O/EtOH solvents by natural cooling. The calculated results show that the (0 1 1) and (0 0 1) faces have large morphological importance in these two solvent systems, and the predicted DNTF morphologies agree qualitatively with those of the observed experimental results. Radial distribution function (RDF) and diffusion coefficient analyses were performed to explore the adsorption and diffusion behaviors of solvent molecules on DNTF surfaces. Furthermore, the impact and friction sensitivities of different crystal morphologies of DNTF were also tested and discussed. Results suggest that crystal morphology is an important impact factor for controlling the sensitivity of explosives.

This work elucidated the underlying mechanism of the dramatic and divergent physicochemical properties of CL-20-based energetic cocrystals.

Cocrystals of hexanitrohexaazaisowurtzitane (CL-20) and 7H-trifurazano[3,4-b:3′,4′-f:3′′,4′′-d]azepine (TFAZ) in a 1 : 1 molar ratio were prepared by both slow evaporation and self-assembly methods. Structure determination showed that they belong to the monoclinic system (space group P2₁) with a crystal density of 1.932 g cm⁻³. The intermolecular hydrogen bonds and N–O⋯NO₂ type interactions are demonstrated as the predominant driving forces in the cocrystal formation. Furthermore, the cocrystals were successfully synthesized by a self-assembly method using only water as a solvent under mild conditions and the product yield was up to 92.3%. The two types of cocrystals were fully characterized by powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Moreover, the thermal behavior, sensitivity, and calculated detonation performance of the cocrystals were evaluated. The cocrystals exhibit good thermal stability (T_d = 242.8 °C), low impact sensitivity (H₅₀ = 42 cm) and friction sensitivity (P_f = 38%), high crystal density, and high calculated detonation velocity (9103 m s⁻¹). This work opens up a new perspective in the environment-friendly preparation of energetic cocrystals on a large-scale, as well as providing potential low-sensitivity and high-energy explosives.

The receptor-like kinase SIT1 acts as a sensor in rice (Oryza sativa) roots, relaying salt stress signals via elevated kinase activity to enhance salt sensitivity. Here, we demonstrate that Protein Phosphatase 2A (PP2A) regulatory subunit B9κ constrains SIT1 activity under salt stress. B9κ-PP2A deactivates SIT1 directly by dephosphorylating the kinase at Thr515/516, a salt-induced phosphorylation site in the activation loop that is essential for SIT1 activity. B9κ overexpression suppresses the salt sensitivity of rice plants expressing high levels of SIT1, thereby contributing to salt tolerance. B9κ functions in a SIT1 kinase-dependent manner. During early salt stress, activated SIT1 phosphorylates B9κ; this not only enhances its binding with SIT1, it also promotes B9κ protein accumulation via Ser502 phosphorylation. Consequently, by blocking SIT1 phosphorylation, B9κ inhibits and fine-tunes SIT1 activity to balance plant growth and stress adaptation.