Molecular design of a new family of bridged bis(multinitro‐triazole) with outstanding oxygen balance as high‐density energy compounds

Abstract

A new family of bridged bis(multinitro-triazole) was designed and investigated using the density functional theory method. The density, oxygen balance, heat of formation, detonation performance, and impact sensitivity were calculated systematically. The results show that the multinitromethyl groups play an important role in increasing densities. At the same time, different bridged groups present diverse performances with high density (1.86-1.96 gÁcm −3 ), excellent detonation properties (V = 8.72 kmÁs −1 -9.20 kmÁs −1 ; P = 34.54 GPa-39.49 GPa), outstanding oxygen balance (0%-11.59%), and acceptably impact sensitivity. Especially, tetrazine (M7)-bridged and diaminofurazan (M9)-bridged groups are very helpful for enhancing their detonation performance (V (M7) = 9.12 kmÁs −1 , P (M7) = 38.51 GPa; V (M9) = 9.20 kmÁs −1 , P (M9) = 39.49 GPa), respectively, which are better than RDX. They could be seen as the potential candidates of high energy density materials (HEDMs). K E Y W O R D Sbridged bis(multinitro-triazole), detonation properties, oxygen balance, DFT | INTRODUCTIONRecently, symmetric compounds with bridging have been found. They are regarded as the most promising strategies in the design of highperformance energetic compounds [1][2][3] with the merits of high density, high positive heat of formation, good detonation performances, and excellent thermal stability. [4][5][6][7][8][9][10] The energetic materials of nitrogen-rich organic compounds increasingly become attracting as the promising candidates in the challenging field of energetic materials research. The traditional sources of energetic materials are five-membered or six-membered nitrogen-containing heterocycles. Especially, triazole, tetrazole, and tetrazine derivatives have always been designed and synthesized as the energetic compounds theoretically and experimentally. [11][12][13] The energetic compounds with bridged groups such as 5,5 0 -dinitro-3,3 0 -azo-1,2,4-triazole [14] or the analog nitrimino compound [15] have shown remarkably high decomposition temperatures and excellent energetic properties. Nowadays, many researchers have investigated the combination of the heterocycles with bistetrazoles [16,17] and bistriazoles [18,19] As components of composite high-energy materials with high density and positive oxygen balance, polynitrogenated compounds are of interest for researchers. [20] Of course, the trinitro group is always deemed as the unit, which can increase density dramatically and improve oxygen balance, thereby enhancing detonation performance. Shreeve and coworkers [21] reported the synthesis of various polynitro-1,2,4 triazoles, which contain trinitromethyl groups and display potentially significant physical and energetic properties. Klapötke [22] team focused the contribution of bis-1,2,4-triazoles carrying nitro, dinitromethyl energetic groups. Semenov [20] presented the 2,2 0 -bis(trinitromethyl)-derivatives formed the N,N 0 -Dinitromethyl derivatives of 5,5 0dinitrobi(1,2,4-triazole) by a sequence of nitration, fluorination, an...

Unimolecular Decomposition Reactions of Picric Acid and Its Methylated Derivatives─A DFT Study

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