Presently, solving the conflict between energy and safety is the main challenge during the exploration of energetic materials. This work reports a special synthesis approach of novel energetic materials with favorable properties across various aspects derived from the pyrazolo[1,5-a]pyrimidine framework. Some compounds with a pyrazolo[1,5-a]pyrimidine skeleton, 2,3-dinitro-6-(1H-tetrazol-5-yl)pyrazolo[1,5-a]pyrimidin-7-amine (4), N-(7-amino-3-nitro-6-(1H-tetrazol-5-yl)pyrazolo[1,5-a]pyrimidin-2-yl)nitramide (5), and 2,3,6-trinitropyrazolo[1,5-a]pyrimidin-7-amine (6), were synthesized. In this work, the strategy of modifying the functional group from a tetrazole group to a nitro group was employed, which is very rare in previous reports. Compounds 4 (ρ = 1.80 g·cm^–3, D = 8508 m·s^–1) and 5 (ρ = 1.85 g·cm^–3, D = 8698 m·s^–1) possess high density, and their detonation velocities approach that of RDX (ρ = 1.82 g·cm^–3, D = 8795 m·s^–1). In particular, through functional group modification from the tetrazole group to the −NO₂ group, the density, detonation velocity, and thermal decomposition temperature of compound 6 with nitro groups (ρ = 1.89 g·cm^–3, D = 8922 m·s^–1, and T_d = 287 °C) show significant improvement compared to compound 4 with a tetrazole group (ρ = 1.80 g·cm^–3, D = 8508 m·s^–1, and T_d = 147.5 °C). Quantum computational methods were also employed to study the association between the performance and structure. Compound 6 (D = 8922 m·s^–1, T_d = 287 °C) displays higher densities, thermal decomposition temperatures, and detonation velocities compared with HMX (D = 9144 m·s^–1, T_d = 280 °C). Moreover, its impact sensitivity and friction sensitivity (IS = 30 J, FS > 360 N) are significantly lower than those of HMX (IS = 5 J, FS = 102 N). Therefore, compound 6 would be a potential candidate for novel high-energy-density materials (HEDMs).

中文翻译：

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吡唑并[1,5-a]嘧啶：一种具有高热稳定性的新型5/6熔融含能材料


当前，解决能源与安全之间的矛盾是含能材料探索的主要挑战。这项工作报告了一种新型含能材料的特殊合成方法，该材料在吡唑并[1,5- a ]嘧啶框架的各个方面具有良好的性能。一些具有吡唑并[1,5- a ]嘧啶骨架的化合物，2,3-二硝基-6-( 1H-四唑-5-基)吡唑并[1,5 -a ]嘧啶-7-胺( 4 )， N- (7-氨基-3-硝基-6-(1 H-四唑-5-基)吡唑并[1,5- a ]嘧啶-2-基)硝酰胺( 5 )和2,3,6-三硝基吡唑并合成了[1,5- a ]嘧啶-7-胺( 6 )。在这项工作中，采用了将官能团从四唑基团修饰为硝基基团的策略，这在之前的报道中是非常罕见的。化合物4 （ρ = 1.80 g·cm ^–3 ， D = 8508 m·s ^–1 ）和5 （ρ = 1.85 g·cm ^–3 ， D = 8698 m·s ^–1 ）具有高密度和爆速接近RDX (ρ = 1.82 g·cm ^–3 , D = 8795 m·s ^–1 )。特别是，通过从四唑基团到-NO ₂基团的官能团修饰，具有硝基的化合物6的密度、爆速和热分解温度(ρ = 1.89 g·cm ^–3 , D = 8922 m·s) ^–1和T _d = 287 °C）与具有四唑基团的化合物4相比（ρ = 1）显示出显着的改进。80 g·cm ^–3 ， D = 8508 m·s ^–1 ， T _d = 147.5 °C）。还采用量子计算方法来研究性能与结构之间的关联。与HMX （ D = 9144 m·s ^–1 ， T _d = 280 °C）相比，化合物6 （ D = 8922 m·s ^–1 ， T _d = 287 °C）具有更高的密度、热分解温度和爆速。 。而且，其冲击灵敏度和摩擦灵敏度（IS = 30 J，FS > 360 N）显着低于HMX （IS = 5 J，FS = 102 N） 。因此，化合物6将成为新型高能量密度材料（HEDM）的潜在候选者。