A) Novel Energetic Cation (ACS Appl. Mater. Interfaces 2024, 16, 47, 64846–64857)

The field of high energy density materials faces a long-standing challenge to achieve an optimum balance between energy and stability. While energetic salt formation via a combination of oxygen- and nitrogen-rich anions (providing energy) with nitrogen-containing cations (providing stability) has been a proven approach for improving physical stability, constraints such as lowering density and energetic performance remain unresolved. This can be addressed by utilizing oxygen-containing cations for salt formation. However, this approach is rarely explored because its synthesis is challenging. In this work, we have designed an oxygen-rich cationic precursor by incorporating 4-amino-3,5-dinitropyrazole with 3,4-diaminotriazole via an N-methylene-C bridge. Further combination with energetic acids resulted in the formation of high-performing, physically stable energetic salts. The salts were found to be generally more energetic than the salts of respective energetic acids with previously reported cations and showed prominent improvement in physical stability with respect to their anionic precursors.

B) Extremely Dense and Thermally Stable Material as a Substitute for Lead Azide (Org. Lett. 2024, 26, 9, 1952–1958) 

Because of environmental and health impacts, there is an ongoing necessity to develop sustainable primary explosives to replace existing lead-based analogues. Now we describe a potential primary explosive, dipotassium 4,6-dinitro-5,7-dioxidobenzo[c][1,2,5]oxadiazole 1-oxide (K2DNDP), which exhibits an excellent thermal stability (Tdec = 281 °C), positive oxygen balance (+4.79%), and a calculated crystal density of ρ = 2.274 g cm–3 at 100 K. Its physicochemical properties concomitantly with its straightforward synthesis make it a potential replacement for lead-based initiators. 

C) Thermally Stable Zwitterionic Energetic Materials (Org. Lett. 2024, 26, 45, 9781–9786) 

4-Hydroxy-3,5-dinitropyrazole (HODNP) was investigated as a precursor for synthesizing two thermally stable, insensitive zwitterionic energetic materials. The ability of the hydroxy functionality to carry negative charge was leveraged and further covalently bonded with two positively charged moieties (3,4-diamino-1,2,4-triazole and acetimidamide) via N-functionalization to form zwitterions 2 and 3. Structural characterization and a study of the energetic performance were carried out. The zwitterionic nature of compound 3 was confirmed by single-crystal analysis. 

D) Taming of 4-azido-3,5-dinitropyrazole based energetic materials (Mater. Adv., 2024,5, 171-182)

4-Azido-3,5-dinitropyrazole (AzDNP) and its derivatives are attractive candidates as high-performance energetic materials due to their excellent energetic properties and high nitrogen and oxygen contents. However, they are often more sensitive (primary explosives) and have poor thermal stability (Td < 150 °C), attributed to the presence of the azido functionality. In this work, we have tried to fine-tune the properties of 4-azido-3,5-dinitropyrazole by connecting it to 5-nitramino-1,2,4-oxadiazole moieties via N-methylene-C bridges. Furthermore, a series of nitrogen-rich energetic salts were prepared from neutral compound by reacting with different nitrogen-rich bases. The physicochemical and energetic properties of all energetic compounds were also investigated. The hydroxylammonium salt (Dv: 8961 m s−1; P: 33.0 GPa) has been found to be the most energetic derivative of AzDNP to date.