Thermally Stable and Insensitive Energetic Cocrystals Comprising Nitrobarbituric Acid Coformers
Abhishek Kumar Yadav, Vikas D. Ghule, Srinivas Dharavath
Abstract
Four novel energetic cocrystals of 5-nitropyrimidine-2,4,6(1 H,3 H,5 H )-trione/nitro barbituric acid (NBA) with energetic coformers 1 H -tetrazol-5-amine (AmTz), 5-(4-nitro-1 H -pyrazol-3-yl)-4 H -1,2,4-triazol-3-amine (NPTA), 1,3-diaminoguanidinehydrochloride (DAG), and 7 H -[1,2,4]triazolo[4,3- b ][1,2,4]triazole-3,6,7-triamine (TATOT) were synthesized for the first time and confirmed by single-crystal X-ray diffraction. Three cocrystals, NBA:AmTz, NBA:NPTA, and NBA:DAG, were obtained in a stoichiometry of 1:1, while NBA:TATOT was obtained with 1:2 stoichiometry. All the presented molecules were synthesized from commercially available inexpensive starting materials in one or two steps. All the cocrystals possess high densities (1.71–1.80 g cm –3 ), excellent thermal stability (222–310 °C), and low impact and friction sensitivity (>40 J and >360 N), which suggest that they are a better replacement for TNT as a core explosive and are close to RDX and HMX as a formulating energetic material. The strong stabilizing hydrogen bonding and vdW interactions are preserved among all the components of cocrystals. These interactions also play a significant role in cocrystal formation. These cocrystals combine the stability of AmTz, NPTA, DAG, and TATOT with the energetic performance of NBA into a homogeneous energetic material.