A series of guanidine salts of 3,6-bis-nitroguanyl-1,2,4,5-tetrazine: green nitrogen-rich gas-generating agent

Nitrogen-rich energetic materials (EMs) have been widely studied because of their high thermal stability, insensitivity, excellent detonation performance and non-toxic characteristics. In particular, these compounds are well applied as gas-generating agents (GGAs). As a nitrogen-rich heterocyclic framework, 1,2,4,5-tetrazine derivatives have shown great potential in the design of GGAs. The guanidine salts of 3,6-bis-nitroguanyl-1,2,4,5-tetrazine (DNGTz), guanidine (G(2)DNGTz) (1), aminoguanidine (AG(2)DNGTz) (2), diaminoguanidine (DAG(2)DNGTz) (3), and triaminoguanidine (TAG(2)DNGTz) (4) have been synthesized and characterized by elemental analysis and FT-IR. The crystal structures of1and2were obtained by X-ray single crystal diffraction. Crystal analysis shows that1and2arrange through zigzag-chain-like assembly and face-to-face geometries, which is helpful in decreasing mechanical sensitivity. The thermal stability and thermal decomposition kinetics of these four salts were studied by Differential Scanning Calorimetry (DSC). Furthermore, the thermogravimetry-Fourier transform infrared-mass spectrometry (TG-FTIR-MS) analysis of thermal decomposition products reveals that the main decomposition gaseous products are H2O, N2O, CO2, NO, N(2)and NH3. Then, the cytotoxicity of the four salts was tested by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) method, and it was found that salts1-4show slight cytotoxicity in mouse fibroblasts (L929), at a concentration of 0.125 mg ml(-1). The insensitivity, low toxicity, and production of clean gases without solid residue after burning of salt1indicate that it can be used as a potential green energetic material for GGAs.