Tetraazapentalene Chemistry: Unexpected Intramolecular Electron Rearrangement Induced by Highly Reactive ψ‐Dinitroso Substituents

Abstract

[1][2][3][4] tetraazaphosphapentalenes (TAPP), [5] tetraazathiapentalenes (TATP), [6][7] tetraazaselenapentalenes (TASP), [8][9] and their derivatives (Scheme 1) are of special interest owing to their unusual electronic structure and chemical behavior which is governed by the striking orientations of the heteroatoms. These heterocyclic systems promise a variety of applications including in organic synthesis, redox chemistry, and in industry, military, and space programs. Some examples of these applications include the derivatization of p-hypervalent heterocyclic TATP, [10][11][12] the synthesis of versatile heterocyclic compounds, [13][14][15] exotic metal carbene chemistry, [16][17][18][19][20] shaped charges for downhole penetrators, [21] and thermally stable high-energy materials. [22][23][24][25][26] Much attention has been focused on the preparation (precursors and methods) and properties of the heterocyclic tetraazapentalenes and their derivatives because their applications depend significantly on their thermal stability, performance, and synthetic practicality.We are interested in the preparation of high-nitrogencontent energetic materials, heterocyclic high-density materials, and green primary explosives for a wide variety of applications through the utilization of tetrazines, [27] tetrazoles, [28] triazines, [29] furazans, [30] triazoles, [31] pyridines, [32] and azetidines.[33] Our interest in heterocyclic tetraazapentalenes was to probe the explosive performance (detonation velocity (V D ) and detonation pressure (P CJ )) of previously synthesized, thermally stable high-energy compounds and to Scheme 1. The structures of tetraazapentalenes (TAPs), tetraazaphosphapentalenes (TAPPs), tetraazathiapentalenes (TATPs), and tetraazaselenapentalenes(TASPs).

Structure–Performance Relationship in Thermally Stable Energetic Materials: Tunable Physical Properties of Benzopyridotetraazapentalene by Incorporating Amino Groups, Hydrogen Bonding, and π–π Interactions

“…All reagents purchased commercially were used as received (Sigma-Aldrich, TCI, Acros, and J&K Organics). BPTAP was prepared according to the literature …”

“…BPTAP was prepared according to the literature. 33 1 H and 13 C NMR spectra were recorded on a 400 MHz (Bruker AVANCE 400) nuclear magnetic resonance spectrometer. Chemical shifts in the 1 H and 13 C spectra are reported relative to Me 4 Si.…”

“…Benzopyridotetraazapentalene (BPTAP) is one of the most thermally stable energetic materials . To the best of our knowledge, though it exhibited superior performance to those of HNS, its poor solubility restricted further modification in morphology and applications as a nanoenergetic material.…”

“…Benzopyridotetraazapentalene (BPTAP) is one of the most thermally stable energetic materials. 33 To the best of our knowledge, though it exhibited superior performance to those of HNS, its poor solubility restricted further modification in morphology and applications as a nanoenergetic material. Meanwhile, its new derivatives have not been released since 2005, and structure−property relationship via this unique fused ring has not been discussed yet.…”

Heat‐Resistant Energetic Materials Deriving from Benzopyridotetraazapentalene: Halogen Bonding Effects on the Outcome of Crystal Structure, Thermal Stability and Sensitivity

“…Benzopyridotetraazapentalene (BPTAP) is a heat‐resistant energetic material, which was firstly synthesized by M.H.V. Hunyh et al from Los Alamos National Laboratory [32]. It showed superior density and detonation performance to those of HNS, especially its remarkably low initiation threshold and critical diameter.…”