Derivatives of 1,5-Diamino-1<i>H</i>-tetrazole: A New Family of Energetic Heterocyclic-Based Salts

1,5-Diamino-1H-tetrazole (2, DAT) can easily be protonated by reaction with strong mineral acids, yielding the poorly investigated 1,5-diaminotetrazolium nitrate (2a) and perchlorate (2b). A new synthesis for 2 is introduced that avoids lead azide as a hazardous byproduct. The reaction of 1,5-diamino-1H-tetrazole with iodomethane (7a) followed by the metathesis of the iodide (7a) with silver nitrate (7b), silver dinitramide (7c), or silver azide (7d) leads to a new family of heterocyclic-based salts. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear NMR spectroscopy, mass spectrometry, elemental analysis, X-ray structure determination, and initial safety testing (impact and friction sensitivity). Most of the salts exhibit good thermal stabilities, and both the perchlorate (2b) and the dinitramide (7c) have melting points well below 100 °C, yet high decomposition onsets, defining them as new (7c), highly energetic ionic liquids. Preliminary sensitivity testing of the crystalline compounds indicates rather low impact sensitivities for all compounds, the highest being that of the perchlorate (2b) and the dinitramide (7c) with a value of 7 J. In contrast, the friction sensitivities of the perchlorate (2b, 60 N) and the dinitramide (7c, 24 N) are relatively high. The enthalpies of combustion (ΔcH°) of 7b−d were determined experimentally using oxygen bomb calorimetry: ΔcH° (7b) = −2456 cal g-1, ΔcH° (7c) = −2135 cal g-1, and ΔcH° (7d) = −3594 cal g-1. The standard enthalpies of formation (ΔfH°) of 7b−d were obtained on the basis of quantum chemical computations using the G2 (G3) method: ΔfH° (7b) = 41.7 (41.2) kcal mol-1, ΔfH° (7c) = 92.1 (91.1) kcal mol-1, and ΔfH° (7d) = 161.6 (161.5) kcal mol-1. The detonation velocities (D) and detonation pressures (P) of 2b and 7b−d were calculated using the empirical equations of Kamlet and Jacobs: D(2b) = 8383 m s-1, P(2b) = 32.2 GPa; D(7b) = 7682 m s-1, P(7b) = 23.4 GPa; D(7c) = 8827 m s-1, P(7c) = 33.6 GPa; and D(7d) = 7405 m s-1, P(7d) = 20.8 GPa. For all compounds, a structure determination by single-crystal X-ray diffraction was performed. 2a and 2b crystallize in the monoclinic space groups C2/c and P21/n, respectively. The salts of 7 crystallize in the orthorhombic space groups Pna21 (7a, 7d) and Fdd2 (7b). The hydrogen-bonded ring motifs are discussed in the formalism of graph-set analysis of hydrogen-bond patterns and compared in the case of 2a, 2b, and 7b.1,5-二氨基-1H-四唑（1,5-Diamino-1H-tetrazole，DAT）可与强酸矿物酸发生质子化反应，得到此前研究较少的硝酸1,5-二氨基四唑鎓（2a）与高氯酸1,5-二氨基四唑鎓（2b）。本文提出了一种全新的合成方法，可避免叠氮化铅作为有害副产物生成。将1,5-二氨基-1H-四唑与碘甲烷（7a）反应后，再使生成的碘代盐（7a）分别与硝酸银（7b）、二硝酰胺银（7c）或叠氮化银（7d）发生复分解反应，可得到一系列新型杂环基盐。所有体系均得到了稳定的盐类产物，并通过振动光谱（红外光谱（IR）、拉曼光谱（Raman））、多核核磁共振波谱、质谱、元素分析、X射线晶体结构解析以及初步安全性测试（撞击感度与摩擦感度）完成了全面表征。大部分盐类均表现出优异的热稳定性，其中高氯酸1,5-二氨基四唑鎓（2b）与二硝酰胺盐（7c）的熔点均远低于100℃，同时具备较高的分解起始温度，因此二者（尤其是7c）可被归类为新型高能离子液体。对结晶态化合物的初步感度测试结果显示，所有产物的撞击感度均较低，其中感度最高的高氯酸1,5-二氨基四唑鎓（2b）与二硝酰胺盐（7c）的撞击感度为7 J。与之相反，高氯酸1,5-二氨基四唑鎓（2b，60 N）与二硝酰胺盐（7c，24 N）的摩擦感度相对较高。采用氧弹量热法实验测定了7b~7d的燃烧焓（ΔcH°），结果为：ΔcH°(7b) = -2456 cal·g⁻¹，ΔcH°(7c) = -2135 cal·g⁻¹，ΔcH°(7d) = -3594 cal·g⁻¹。基于G2（G3）量子化学计算方法，得到了7b~7d的标准生成焓（ΔfH°）：ΔfH°(7b) = 41.7（41.2）kcal·mol⁻¹，ΔfH°(7c) = 92.1（91.1）kcal·mol⁻¹，ΔfH°(7d) = 161.6（161.5）kcal·mol⁻¹。采用卡姆莱-雅各布斯（Kamlet and Jacobs）经验公式，计算得到了2b与7b~7d的爆速（D）与爆压（P）：D(2b)=8383 m·s⁻¹，P(2b)=32.2 GPa；D(7b)=7682 m·s⁻¹，P(7b)=23.4 GPa；D(7c)=8827 m·s⁻¹，P(7c)=33.6 GPa；D(7d)=7405 m·s⁻¹，P(7d)=20.8 GPa。所有化合物均通过单晶X射线衍射完成了结构解析。其中2a与2b分别以单斜晶系空间群C2/c与P2₁/n结晶。7系列盐类则以正交晶系空间群Pna2₁（7a、7d）与Fdd2（7b）结晶。本文采用氢键模式图集分析的形式化方法，对氢键环基元进行了讨论，并针对2a、2b与7b的氢键环基元进行了对比分析。