Energetic Nitrogen‐Rich Polymers with a Tetrazene‐Based Backbone

Abstract

New energetic polymers were synthesized from monomers containing a trans-2-tetrazene unit. In contrast to traditional binders, such as inert hydroxytelechelic polybutadiene or glycidyl azide polymers-in which the energetic features are on the side chains-the energetic groups in the polytetrazenes are incorporated directly in the polymer backbone. Thermal analyses demonstrated that decomposition occurs at approximately 130 8C, regardless of the polymer structure. Glass-transition temperatures ranged from À34.2 to 0.2 8C and could be lowered further (to À61 8C) with the help of a new diazidotetrazene energetic plasticizer. Interestingly, hexafluoroisopropanol (HFIP) enabled complete, room-temperature depolymerization within 1 week. This depolymerization should enable the recycling of unused pyrotechnic compositions based on these new binders.

Site-specific DNA functionalization through the tetrazene-forming reaction in ionic liquids

“…S14 †). On the other hand, alkyl-substituted tetrazene compounds could be substantially more stable; for instance, thermal decomposition temperature of a polymer form of tetraalkyl-substituted tetrazene occurs at 130 C. 59 Monoalkyl-substituted tetrazene's 1 H NMR has been reported without special notes about the stability, 47 which is also indicative of reasonable stability of the compound at ambient conditions. Our previous report indicated the product of amine-azide coupling reactions on proteins are stable toward heat denaturing condition (95 C for 2 min) as well as biologically relevant molecules such as glutathione (thiol), hydrogen peroxide, and acidic/basic pH.…”

An Ionic Liquid Medium Enables Development of a Phosphine-Mediated Amine–Azide Bioconjugation Method

“…Even after exposure of the biotinylated protein to various conditions, the presence of more than 80% of the biotin was observed by antibiotin Western blot, showing the retention of the modifications on the proteins (Figures 3D and S26), which is consistent with the known structure-and substituent-dependent stability of tetrazene groups. 36,37 Retention of the modification was also confirmed on samples exposed to typical biochemical analysis conditions such as surfactant, heating (95 °C), and exposure to a reducing agent (Figures S26 and S27).…”

“…Beyond the bioconjugation field, the present report also highlights the breadth of the reactivity of azide groups behaving as electrophiles (i.e., umpolung reactivity): while phosphine-mediated azide reactions (i.e., phosphazide − and iminophosphorane , ) are known to cause nucleophilic attack toward various electrophiles, − covalent bond formation with nucleophiles (amine groups) is unprecedented. Perhaps ionic-liquid-mediated reactivity enhancement plays a key role in the activation of the reaction intermediates (Figure S35), − promoting the electrophilic nature of the phosphine azide species to cause the N–N bond formation reaction. , Interestingly, although nitrogen-rich functional groups such as diazirine, azide, and tetrazine have been extensively studied and utilized in a wide variety of chemistry fields, ,, tetrazene is extremely understudied to date, presumably because of the dearth of mild and selective synthetic methodologies. , Given the excellent chemoselectivity as well as the abundance of amine- or azide-containing molecules, the present method provides new opportunities for the investigation of the tetrazene group.…”

“…51,52 Interestingly, although nitrogen-rich functional groups such as diazirine, azide, and tetrazine have been extensively studied and utilized in a wide variety of chemistry fields, 10,53,54 tetrazene is extremely understudied to date, presumably because of the dearth of mild and selective synthetic methodologies. 36,55 Given the excellent chemoselectivity as well as the abundance of amine-or azide-containing molecules, the present method provides new opportunities for the investigation of the tetrazene group.…”

Catalytic Aerobic Oxidation of Hydrazines into 2‐Tetrazenes

“…They can be used as reagents for amino-hydroxylations of olefins, [1] initiators for radical polymerization, [2][3][4][5][6] or ligands for transition metals. [7][8][9][10] When the molecules are stripped from most substituents, tetrazenes become energetic and could be used for propulsion [11,12] or pyrotechnic [13][14][15][16] purposes.…”