Energetic Triazolo‐Triazolo‐Furazano‐Pyrazines: A Promising Fused Tetracycle Building Block with Diversified Functionalities and Properties

Abstract

In this study, high energy materials (HEMs) derived from 1,2,4‐triazolo[3,4‐d]‐1,2,4‐triazolo[3,4‐f]furazano[3,4‐b]pyrazine (TTFP) substituted with −NH2, −NHNO2, −ONO2, −NO2, and −N3 explosophoric groups were designed and computationally characterized. Density functional calculations with B3PW91/6‐31G(d,p) method were used to explore the optimized structures, energetic properties, and sensitivity of TTFP derivatives. It is found that the TTFP is an effective molecular backbone for improving the energy content and energetic performance of the designed compounds. The effect of various explosophoric groups on energy content, density, detonation performance, and sensitivity was investigated. The energetic evaluation indicated that TTFP derivatives having −NHNO2 (F4), −ONO2 (F5), and −NO2 (F6) groups demonstrate good detonation performances and exceed the performance of TNT and close to that of RDX. Compounds F4‐F6 displays the best energetic properties (density > 1.85 g/cm3, detonation velocity >8.30 km/s, detonation pressure > 32.0 GPa). Considering the energetic properties, the TTFP backbone can be regarded as an energy‐rich unit, which can be substituted with suitable explosophoric groups for constructing HEMs.

Establishing the Analogy between Hydrates and Peroxosolvates: Cambridge Structural Database Analysis of Pyridyl Hydrates Yields New Peroxosolvates

“…Common sp 2 nitrogen-containing moieties in energetic compounds include five- and six-membered heterocycles with one or more nitrogen on the ring (including triazoles, tetrazoles, pyrazines, and triazines). − Pyridine was selected as a test case for an sp 2 nitrogen-containing aromatic ring that would likely yield coformers due to the large number of pyridine-containing hydrates in the CSD (over a thousand) and its predicted strong interactions with hydrogen peroxide . Additionally, despite the large number of hydrates, there are only two examples of organic peroxosolvates with a pyridine-containing coformer (SEMXIU and UKEFEV), and in only one case, 2,3,5,6-tetrakis­(pyridin-2-yl)­pyrazine, do close contacts exist between the pyridine sp 2 nitrogen and H 2 O 2 (the four pyridyl groups accept hydrogen bonds from H 2 O 2 ).…”

Computational investigation and screening of high‐energy‐density materials: Based on nitrogen‐rich 1,2,4,5‐tetrazine energetic derivatives

“…Meanwhile, its characteristics of high nitrogen and low hydrocarbon content make it have the dual effect of not only increasing the material density, but also achieving better oxygen balance easily. [ 3,4 ] Among them, the nitrogen content of tetrazine compounds reached 68.3% is a very effective structural unit in the design of high‐energy insensitive energy‐containing materials, tetrazine compounds have high thermal stability, high positive heats of formation (HOF) and low sensitivity, because of their powerful N–N and C–N bonds. [ 5‐8 ] With the increase of oxygen atoms coordinated with tetrazine, the density and properties of the molecule are improved, and the whole molecule tends to be stable.…”