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


目前，解决能源与安全之间的冲突是探索含能材料过程中的主要挑战。这项工作报道了一种新型含能材料的特殊合成方法，该方法在各个方面都具有良好的性能，源自吡唑并[1,5-a]嘧啶骨架。一些具有吡唑并[1,5-a]嘧啶骨架、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-（1H-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[1,5-a]嘧啶-7-胺（6），被合成。在这项工作中，采用了将官能团从四唑基团修饰为硝基的策略，这在以前的报道中非常罕见。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，其爆炸速度接近 RDX （ρ = 1.82 g·cm^–3， D = 8795 m·s^–1）。特别是，通过从四唑基团到 −NO₂ 基团的官能团修饰，与具有四唑基团的化合物 4 （ρ = 1.80 g·cm–3， D = 8922 m·s^–1， T_d = 287 °C） 相比，具有硝基的化合物 6 的密度、爆炸速度和热分解温度 （ρ = 1.89 g·cm^–3， D = 8508 m·s^–1，T _d = 147.5 °C）。 还采用了量子计算方法来研究性能与结构之间的关联。化合物 6 （D = 8922 m·s^–1， T_d = 287 °C） 与 HMX （D = 9144 m·s^–1， T_d = 280 °C） 相比，表现出更高的密度、热分解温度和爆轰速度。此外，其冲击敏感性和摩擦敏感性 （IS = 30 J， FS > 360 N） 明显低于 HMX （IS = 5 J， FS = 102 N）。因此，化合物 6 将是新型高能量密度材料 （HEDM） 的潜在候选者。