Access to Green Pyrotechnic Compositions via Constructing Coordination Polymers: A New Approach to the Application of 3,4-Dinitropyrazole

Alkali and alkaline-earth metal salts with 3,4-dinitropyrazole
(DNP) were synthesized by the reaction of DNP with stoichiometric
amounts of the corresponding metal hydroxide-, oxide-, or carbonate-based
highly pure salts, and products were fully characterized. Determination
of single-crystal structures of all new complexes except for the lithium
and strontium salts was performed by X-ray diffraction techniques.
The cesium salt crystallized no water among them. Differential scanning
calorimetry (DSC) and thermogravimetric analysis (TGA) manifested
that these salts have satisfactory thermal stabilities with decomposition
temperatures above 210 °C. They also showed that there exists
strong bonding of crystallized water among lattices, which disappeared
at temperatures equal to or above 115 °C except for salts MES-3, MES-4, and MES-9. In addition,
the percentage of water contents was confirmed by using DSC and TGA
methods. The constant-volume combustion heats of these metal salts
containing DNP anions were measured using an oxygen bomb calorimeter
due to their expectant interest in energetic materials, and their
standard molar formation enthalpies were obtained. The investigated
salts were found to be insensitive toward friction and impact. Findings
of burning tests performed with experimental formulations using MES-1, MES-7, MES-8, and MES-9 certify that these four salts might be more promising candidates
for application in green pyrotechnics.