Nitrotetrazolate-2<i>N</i>-oxides and the Strategy of <i>N</i>-Oxide Introduction

The first anionic tetrazole-2N-oxide has been prepared by mild aqueous oxidation of easily prepared 5-nitrotetrazole with commercially available oxone in high yields. The result of protonating 5-nitrotetrazolate-2N-oxide has been identified as a hydroxytetrazole, and the nitrogen-rich salts including ammonium, hydroxylammonium, guanidinium, aminoguanidinum, diaminoguanidinium, and triaminoguanidinium have been prepared and characterized. When compared to the nitrogen-rich salts of nitrotetrazole, the nitrogen-rich salts of nitrotetrazole-2N-oxide show superior energetic performance as calculated by the EXPLO5 computer code, using heats of formation calculated using the CBS-4M level of quantum mechanical theory. The impact, friction, and electrical spark sensitivities of the nitrogen-rich nitrotetrazolate-2N-oxides were measured and cover the whole range from sensitive to insensitive energetic materials.本研究通过以市售过硫酸氢钾复合盐（oxone）为氧化剂，对易合成的5-硝基四唑进行温和水相氧化，以较高收率成功制备出首例阴离子型四唑-2N-氧化物（anionic tetrazole-2N-oxide）。对5-硝基四唑-2N-氧化物负离子进行质子化反应的产物被鉴定为羟基四唑；本研究还制备并表征了一系列富氮盐，涵盖铵盐、羟胺盐、胍盐、氨基胍盐、二氨基胍盐及三氨基胍盐。借助EXPLO5计算代码，并采用基于CBS-4M量子力学理论水平计算得到的生成焓进行性能测算，结果表明：相较于硝基四唑富氮盐，硝基四唑-2N-氧化物富氮盐展现出更优异的含能性能。研究人员测定了这类富氮硝基四唑-2N-氧化物盐的冲击感度、摩擦感度与电火花感度，其性能覆盖了从敏感型到钝感型含能材料的全部区间。