Alkali metals dancing with 4,5-bis(1-hydroxytetrazol-5-yl)-2H-1,2,3-triazole: A family of energetic coordination polymers as prospective green pyrotechnics

Energetic coordination polymers (ECPs) with alkali metals remain at the forefront of pyrotechnics research due to their enormous potential for improving the safety and compatibility of pyrotechnics. Herein, we selected 4,5-bis(1-hydroxytetrazol-5-yl)-2H-1,2,3-triazole (H3OBTT) as the energetic linker because of its high nitrogen content (64.98%), abundant coordination sites, and good thermal stability (Tp = 246 degrees C). A family of new ECPs, namely, [Li2(HOBTT) (H2O)]n center dot 2H2O (1), [Na2(HOBTT)(H2O)2]n center dot H2O (2), [K(H2OBTT)]n (3), and [Cs2(HOBTT)]n (4), were successfully prepared and characterized. Among them, 3 and 4 displayed three-dimensional solvent-free frameworks. They exhibit excellent thermal stabilities (Tdec>280 degrees C) and mechanical sensitivities (IS > 40 J, FS > 250 N). The flame colors of 1-4 were largely due to the unique excitation of different alkali metals ranging from red to yellow. The dynamic com-bustion of 1-4 discovered that the combustion duration of 3 was more than 1.720 s, and its flame stability time reached 1.400 s. Additionally, 3 was simple to prepare under mild conditions with a short reaction time, making it prospective green pyrotechnic candidates. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Energetic coordination polymers (ECPs) with alkali metals have great potential for improving the safety and compatibility of pyrotechnics. In this study, a series of new ECPs were synthesized using a compound with high nitrogen content, abundant coordination sites, and good thermal stability as the energetic linker. One of the ECPs showed good thermal stability and mechanical sensitivity, and could be a prospective green pyrotechnic candidate.