Expanding the Limits of Organic Energetic Materials: High-Performance Alliance of 1,3,4-Thiadiazole and Furazan Scaffolds.

Abstract

A majority of known and newly synthesized energetic materials comprise polynitrogen or nitrogen-oxygen heterocycles with various explosophores. However, available structural combinations of these organic scaffolds are finite and are about to reach their limits. Herein, we present the design and synthesis of a series of sulfur-containing polyazole structures comprising 1,3,4-thiadiazole and furazan rings linked by C-C bonds and enriched with energetic nitro and azo functionalities. In terms of detonation performance, all synthesized 1,3,4-thiadiazole-furazan assemblies (D = 7.7-7.9 km s-1; P = 26-28 GPa) lie between the powerful explosive TATB (D = 8.0 km s-1; P = 31 GPa) and melt-cast material TNT (D = 6.9 km s-1; P = 23 GPa). In the synthesized series, azo-bridged derivative 5 seems to be most practically interesting, as it combines a relatively high energetic performance (D = 7.9 km s-1; P = 28 GPa), a very high thermal stability (271 °C), and insensitivity to friction. By these functional properties, 5 outperforms the benchmark heat-resistant explosive hexanitrostilbene (HNS). To the best of our knowledge, this is the first example of an energetic alliance of furazan and 1,3,4-thiadiazole scaffolds and a rare case of sulfur-containing high-energy materials, which can certainly be considered as an evolutionary step in energetic materials science.