Development of high-density energetic materials has drawn considerable attention because the densities significantly affect their detonation performance. Herein, we propose an effective strategy based on positional isomerism for enhancing the densities of pre-existing energetic materials by optimizing their structures to reinforce intermolecular interactions. By applying this strategy, we design and synthesize 2-amino-5-nitramino-1,3,4-oxadiazole (2), a suitable isomer of 3-amino-5-nitramino-1,2,4-oxadiazole (1). This isomer is the first example of a monocyclic nitramino 1,3,4-oxadiazole reported to date. Single-crystal X-ray diffraction reveals that the isomer has a high crystal density (1.938 g cm⁻³ at 110 K), which is 0.083 g cm⁻³ greater than that of the original material (1, 1.855 g cm⁻³ at 110 K). Mechanistic studies confirmed that the isomer possesses stronger intermolecular hydrogen-bonding and π − π interactions, resulting in denser stacking, smaller cell volume, and thus, higher density. Remarkably, the isomer has a very short intermolecular hydrogen bond (1.956 Å), which is significantly shorter than that of 1 (2.133 Å) and other representative strongly hydrogen-bonded energetic materials such as 2,4,6-triamino-1,3,5-trinitrobenzene (TATB, 2.239 Å) and 1,1-diamino-2,2-dinitroethylene (FOX-7, 2.143 Å). Moreover, this strategy can be applied to its energetic salts. The higher densities of the isomer and its salts endow better detonation performance. Particularly, the detonation velocity of the isomer is more than 400 m s⁻¹ higher than that of the original material (8668 m s⁻¹ for 2 vs 8250 m s⁻¹ for 1). Meanwhile, the hydroxylammonium salt 2b exhibits a high detonation velocity of 9087 m s⁻¹, which is superior to that of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX).

高密度含能材料的发展引起了相当多的关注，因为密度显着影响其爆轰性能。在此，我们提出了一种基于位置异构的有效策略，通过优化其结构以增强分子间相互作用来提高预先存在的含能材料的密度。通过应用此策略，我们设计并合成了 2-amino-5-nitramino-1,3,4-oxadiazole ( 2 )，这是 3-amino-5-nitramino-1,2,4-oxadiazole ( 1 )的合适异构体. 这种异构体是迄今为止报道的单环硝基氨基 1,3,4-恶二唑的第一个例子。单晶X-射线衍射表明，异构体具有高的晶体密度（1.938克厘米^-3，在110 K），其是0.083克厘米^-3大于原始材料的 ( 1 , 1.855 g cm ^-3 at 110 K)。机理研究证实，该异构体具有更强的分子间氢键和 π - π 相互作用，导致堆积更密，细胞体积更小，因此密度更高。值得注意的是，该异构体具有非常短的分子间氢键 (1.956 Å)，明显短于1(2.133 Å) 和其他具有代表性的强氢键高能材料，如 2,4,6-triamino-1,3,5-trinitrobenzo (TATB, 2.239 Å) 和 1,1-diamino-2,2-dinitroethylene (FOX) -7, 2.143 埃)。此外，这种策略可以应用于其高能盐。异构体及其盐的密度越高，爆轰性能越好。特别是，异构体的爆速比原始材料高400 m s ^-1以上（8668 m s ^-1 for 2 vs 8250 m s ^-1 for 1）。同时，羟铵盐2b表现出9087 m s ^-1的高爆速，优于 1,3,5-trinitroperhydro-1,3,5-triazine (RDX)。