A series of highly energetic organic salts comprising a tetrazolylfuroxan anion, explosophoric azido or azo functionalities, and nitrogen‐rich cations were synthesized by simple, efficient, and scalable chemical routes. These energetic materials were fully characterized by IR and multinuclear NMR (1H, 13C, 14N, 15N) spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Additionally, the structure of an energetic salt consisting of an azidotetrazolylfuroxan anion and a 3,6,7‐triamino‐7H‐[1,2,4]triazolo[4,3‐b][1,2,4]triazolium cation was confirmed by single‐crystal X‐ray diffraction. The synthesized compounds exhibit good experimental densities (1.57–1.71 g cm−3), very high enthalpies of formation (818–1363 kJ mol−1), and, as a result, excellent detonation performance (detonation velocities 7.54–8.26 kms−1 and detonation pressures 23.4–29.3 GPa). Most of the synthesized energetic salts have moderate sensitivity toward impact and friction, which makes them promising candidates for a variety of energetic applications. At the same time, three compounds have impact sensitivity on the primary explosives level (1.5–2.7 J). These results along with high detonation parameters and high nitrogen contents (66.0–70.2 %) indicate that these three compounds may serve as potential environmentally friendly alternatives to lead‐based primary explosives.
Several energy-rich bifuroxans incorporating nitro and azido functionalities have been synthesized and thoroughly characterized by IR and multinuclear NMR spectroscopy, elemental analyses, single-crystal X-ray diffraction, and differential scanning calorimetry. N-oxide regiochemistry was employed to design the tunable azido(nitro)bifuroxans with different physicochemical and energetic properties. All synthesized compounds have high enthalpies of formation (449−777 kJ mol −1 ) and attractive performances, as evidenced by the high detonation velocities (8.95−9.75 km s −1 ) and Champan−Jouguet pressures (35−45 GPa). The most powerful energetic material in this series is 4,4′-dinitro-3,3′-bifuroxan. This hydrogen-free molecule (C 4 N 6 O 8 ) exhibits an outstanding heat of explosion value of 15.3 kJ cm −1 , far exceeding the top energetic material hexanitrohexaazaisowurtzitane CL-20. At the same time, the impact and friction sensitivities of 4,4′-dinitro-3,3′-bifuroxan were deemed acceptable for practical use. Overall, 4,4′-dinitro-3,3′-bifuroxan breaks a general trend called the "energy-sensitivity rule", which describes a linear increase of the mechanical sensitivity with a growth of the energetic content of the molecule, and, thus, offers great promise for future applications.
A series of novel energetic materials comprising of azo-bridged furoxanylazoles enriched with energetic functionalities was designed and synthesized. These high-energy materials were thoroughly characterized by IR and multinuclear NMR ( 1 H, 13 C, 14 N) spectroscopy, high-resolution mass spectrometry, elemental analysis, and differential scanning calorimetry (DSC). The molecular structures of representative amino and azo oxadiazole assemblies were additionally confirmed by single-crystal X-ray diffraction and X-ray powder diffraction. A comparison of contributions of explosophoric moieties into the density of energetic materials revealed that furoxan and 1,2,4-oxadiazole rings are the densest motifs while the substitution of the azide and amino fragments on the nitro and azo ones leads to an increase of the density. Azo bridged energetic materials have high nitrogen-oxygen contents (68.8-76.9 %) and high thermal stability. The synthesized compounds exhibit good experimental densities (1.62-1.88 g cm À 3 ), very high enthalpies of formation (846-1720 kJ mol À 1 ), and, as a result, excellent detonation performance (detonation velocities 7.66-9.09 km s À 1 and detonation pressures 25.0-37.7 GPa). From the application perspective, the detonation parameters of azo oxadiazole assemblies exceed those of the benchmark explosive RDX, while a combination of high detonation performance and acceptable friction sensitivity of azo(1,2,4-triazolylfuroxan) make it a promising potential alternative to PETN.
A series of highly energetic nitrogen-rich salts comprised of a 5-(trinitromethyl)tetrazolate anion and high-nitrogen cations was synthesized by simple and efficient chemical routes from readily available commercial reagents. These energetic...
The title methods involve the [4+2] cycloaddition of enamine or norbornadiene to the triazine ring of triazinfuroxans followed by one‐pot transformation of the formed intermediates affording a series of polyheterocyclic compounds combining furoxan and pyridine rings in one molecule through a C—C bond.
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