Aminonitro Groups Surrounding a Fused Pyrazolotriazine Ring: A Superior Thermally Stable and Insensitive Energetic Material

Abstract

Nitrogen-rich heterocyclic compounds offer promising potential backbones for constructing various high energy density compounds. Selective diazotization of 3,5-diamino-4-nitropyrazole (1) with tert-butyl nitrite followed by treatment with the sodium salt of nitroacetonitrile gives rise to a fused pyrazolotriazine ring (5) surrounded by amino and nitro groups. Compound 5, confirmed by single-crystal X-ray diffraction, has a remarkable thermal decomposition temperature of 355 °C, a high density of 1.90 g cm–3, and low impact and friction sensitivities. The detonation performance is also superior to TATB. These advantages make 5 a promising candidate as a heat-resistant explosive.

Energetic Butterfly: Heat-Resistant Diaminodinitro trans-Bimane

“…The development of new heat-resistant energetic materials (EMs) with improved thermostability is of great interest for a broad range of civil and defense applications. For example, in the aerospace industry, thermostable EMs are essential for providing unique solutions for stringent requirements for reliable and safe space-craft stage-separations and gear deployment [1,2,3]. In the case of deep-well oil and gas drilling, perforating guns, based on thermostable EMs, ensure efficient penetration and easier access to soil-embedded deposits at great depth, where temperatures may reach above 250 °C [4,5].…”

Taming nitroformate through encapsulation with nitrogen-rich hydrogen-bonded organic frameworks

“…5) show that the activation energies are 293.4 and 287.2 kJ mol −1 (Supplementary Table 3), respectively. These values are not only considerably higher than those of classic explosives 2,4,6trinitrotoluene (TNT~115 kJ mol −1 ) 44 , cyclotrimethylenetrinitramine (RDX~150 kJ mol −1 ), but also higher than that of TATB (~211 kJ mol −1 ) 45 , which indicates that HOF-NF has excellent heat-resistant properties, and it is an excellent candidate as a steady and reliable explosive. The insensitivity, high thermostability and high heat-resistance of HOF-NF result from the electrostatic interaction between NF anions and the surrounding strengthened cationic frameworks and the fact that all O atoms of the NF anion are stabilized through H-bonding.…”

Nitroacetonitrile as a versatile precursor in energetic materials synthesis

“…The potassium salt of nitroacetonitrile is an excellent alternative to neutral nitroacetonitrile being thermodynamically stable, chemically equivalent, and water-soluble; in fact, many syntheses using nitroacetonitrile begin with the formation of a nitroacetonitrile salt in situ 6,14,15,27,[47][48][49][50] The potassium salt of nitroacetonitrile can be obtained from the hydrolysis of the potassium salt of ethyl nitrocyanoacetate into the unstable dipotassium salt of nitrocyanoacetic acid (cyano-aci-nitroacetate) which readily converts, via decarboxylation, into the potassium salt of nitroacetonitrile (Scheme 7) with a 45% yield. 31 The nitroacetonitrile potassium salt has also been obtained with a 79% yield by the decarboxylation of an acidic aqueous solution of dipotassium nitrocyanoacetic acid through an ion-exchange resin (IRC-50).…”

“…The addition of the vicinal amino and nitro group structural motif stabilizes via intra-and intermolecular hydrogen bonding. 6,50 The presence of amine and nitro groups can lead to conjugation resulting in a planar structure with p-p stacking interactions. These interactions are also seen in fused-rings with at molecular geometry.…”