Advancement and stabilization of copper(ii) azide by the use of triazole- and tetrazole ligands – enhanced primary explosives

Abstract

Stabilization of copper(ii) azide by application of various nitrogen-rich azole ligands resulted in a series of powerful energetic coordination compounds with desired properties for primary explosives.

4,4′-Azobis(1,2,4-triazole): A Versatile Molecular Scaffold to Develop Tailor-Made Energetic Materials

“…3−5 On the contrary, azolecontaining materials are usually fairly insensitive in nature despite their high energy density. 4,6,7 Nitrogen-rich energetic materials exhibit high heats of formation and good thermal stability in general. 6 N−N single bond is relatively weak due to electronic repulsion among the lone pairs, while N�N triple bond is much stronger.…”

“…This class of compounds exhibit a wide range of sensitivities based on the functionalities present. For example, presence of azido group increases sensitivities to impact and friction significantly. − On the contrary, azole-containing materials are usually fairly insensitive in nature despite their high energy density. ,, Nitrogen-rich energetic materials exhibit high heats of formation and good thermal stability in general . N–N single bond is relatively weak due to electronic repulsion among the lone pairs, while NN triple bond is much stronger.…”

Cupric coordination compounds with multiple anions: a promising strategy for the regulation of energetic materials

“…13–17 For example, N 3 − (azide ions) gives the complex higher mechanical sensitivity and strong detonation ability, while DCA − (dicyandiamide ions) gives the complex better thermal stability, lower sensitivity, and higher combustion heat. 18,19 Another example is the preparation of Cu(N 3 ) 2 (L) (L = 1-methyltetrazole (MTZ), 1-ethyltetrazole (ETZ), and 1-propyltetrazole (PTZ)), which regulates the stability and mechanical sensitivity of copper azide by changing the ligand. 20 By changing the central metal ion, mechanical sensitivity, thermal decomposition temperature, and combustion heat of the energetic compounds can all be changed.…”

Cu-Electrocatalytic Diazidation of Alkenes at ppm Catalyst Loading

“…While transition metal catalyzed alkene 1,2-diazidation remains the most efficient method for the preparation of vicinal diazides, the cumulation of hazardous metal azides at high catalyst loading causes significant safety concerns. − Hence, it is highly desirable to reduce the metal catalyst loading and address the limited efficiency of the diazidation of electron-deficient alkenes. Like many transition metal catalyzed radical reactions, a key step in the diazidation involves ligand transfer from the metal catalyst to a transient alkyl radical (Figure B), − which exists at very low concentration.…”

“…A key role of K 3 PO 4 is to promote the hydrolysis of TMSN 3 to N 3 – , as indicated by additional voltammetric studies (Figure S3). Note that the copper azide species Cu III (N 3 ) 3 , Cu II (N 3 ) 2 , and Cu I (N 3 ) are simplified formulas for the purpose of presentation but likely to exist as more complex polymeric species. , Our hypothesis on the success of the electrochemical diazidation with low catalyst loading is that the diazidation process occurs near the electrode surface instead of in the bulk solution. In this scenario, the reactive copper species and the intermediate alkyl radical concentrate in a small space with relatively high concentration, allowing the use of a low catalyst loading.…”