Splicing oxygen-rich multidentate ligands and characteristic metals to construct flame colorants: abundant structures and attractive colors

Tetranitroethane (TNE), an energetic compound with high-nitrogen (N%, 26.7%) and oxygen (O%, 60.9%) content, is deprotonated by alkali and alkaline earth metal bases to form the corresponding metal salts of TNE which are characterized by FT-IR spectroscopy, elemental analysis, and single crystal X-ray diffraction. All the prepared energetic metal salts show excellent thermal stabilities, and the decomposition temperatures of EP-3, EP-4, and EP-5 are higher than 250 °C, due to the numerous coordination bonds of the complexes. Furthermore, the energy of formation of the nitrogen-rich salts were calculated utilizing heat of combustion. The detonation performances were calculated with the EXPLO5 software, and the impact and friction sensitivities were determined. EP-7 shows excellent energy performance (P = 30.0 GPa, V_D = 8436 m s⁻¹). EP-3, EP-4, EP-5, and EP-8 are more sensitive to mechanical stimulation. These alkali and alkaline earth metal salts of TNE show good monochromaticity by atomic emission spectroscopy (visible light), and may be used as potential flame colorants in pyrotechnics.