N‐Oxide 1,2,4,5‐Tetrazine‐Based High‐Performance Energetic Materials

Abstract

One route to high density and high performance energetic materials based on 1,2,4,5-tetrazine is the introduction of 2,4-di-N-oxide functionalities. Based on several examples and through theoretical analysis, the strategy of regioselective introduction of these moieties into 1,2,4,5-tetrazines has been developed. Using this methodology, various new tetrazine structures containing the N-oxide functionality were synthesized and fully characterized using IR, NMR, and mass spectroscopy, elemental analysis, and single-crystal X-ray analysis. Hydrogen peroxide (50 %) was used very effectively in lieu of the usual 90 % peroxide in this system to generate N-oxide tetrazine compounds successfully. Comparison of the experimental densities of N-oxide 1,2,4,5-tetrazine compounds with their 1,2,4,5-tetrazine precursors shows that introducing the N-oxide functionality is a highly effective and feasible method to enhance the density of these materials. The heats of formation for all compounds were calculated with Gaussian 03 (revision D.01) and these values were combined with measured densities to calculate detonation pressures (P) and velocities (νD ) of these energetic materials (Explo 5.0 v. 6.01). The new oxygen-containing tetrazines exhibit high density, good thermal stability, acceptable oxygen balance, positive heat of formation, and excellent detonation properties, which, in some cases, are superior to those of 1,3,5-tritnitrotoluene (TNT), 1,3,5-trinitrotriazacyclohexane (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX).

Energetic 1,2,5‐Oxadiazolo‐Pyridazine and its N‐Oxide

“…Based on previous oxidation studies by using HOF or a mixture of 50 % hydrogen peroxide and trifluoroacetic anhydride, we selected 4,7‐diaminopyridazino[4,5‐ c ]furoxan ( 5 ) as the substrate, which could be converted to the nitro substituted compound A (Scheme ). Compound A had been discussed theoretically and showed promising properties in the application of solid composite propellants .…”

Synthesis, Characterization, and Energetic Properties of 6‐Amino‐tetrazolo[1,5‐b]‐1,2,4,5‐tetrazine‐7‐N‐oxide: A Nitrogen‐Rich Material with High Density

“…All of them contain azido group(s) adjacent to heteroaromatic nitrogen rings which could be incorporated into fused tetrazole rings. The reaction of peroxytrifluoroacetic acid (PTFA) has been found to be very a successful medium for introducing the N‐oxide moiety 15…”

“…The reactiono fp eroxytrifluoroacetic acid (PTFA) has been found to be very as uccessful medium for introducing the N-oxide moiety. [15] However,t his methodology was not successful in forming the N-oxide derivative of 1 or 2.F ortunately,c ompound 3, [16] which contains 81 %n itrogen by weight, can be converted very smoothly into the N-oxide, 4,i n4 2% yield (Scheme 1).…”

The Pyridazine Scaffold as a Building Block for Energetic Materials: Synthesis, Characterization, and Properties

“…[10,11] The same effect is observed for LLM-105 (ρ = 1.92 g•cm -3 , D C-J = 8516 m•s -1 ) and its precursor 2,6-diamino-3,5-dinitropyrazine (ANPZ, ρ = 1.84 g•cm -3 , D C-J = 7892 m•s -1 ). [7,12] (Figure 1 Recently, in our research group we managed to functionalize the 1,2-diazine scaffold by synthesizing 3,5-diamino-4,6dinitropyridazine-1-oxide and its precursor 3,5-dimethoxy-4,6dinitropyridazine-1-oxide. [13] For this purpose, a selective functionalization of the pyridazine scaffold was carried out by introducing explosophore NO 2 groups and selectively introducing a N + -Omoiety.…”

“…Hydrogen radii are arbitrary. Selected bond lengths reported in Å and angles reported in°: N1-N2 1.3289(17), N1-C4 1.3645(18), N2-C1 1.3553(18), C1-C2 1.4408(19), C2-C3 1.432(2), C3-C4 1.4057(19), O1-N1 1.2577(15), N3-C1 1.3238(19), N3-C5 1.4717(19), N4-C2 1.4234(18), O2-N4 1.2403(17), O4-N6 1.2215(17), N5-C7 1.4611(19), N1-N2-C1 116.76(12), C4-C3-C2 113.49(12), O1-N1-N2 117.12(11), C1-N3-C5 120.74(13), C6-N3-C5 115.07(13), C7-N5-C8 113.46(12), N1-…”