Regulating the melting point by non-covalent interaction toward a promising insensitive melt-castable energetic material: 1,2-difluoro-4,5-dinitrobenzene

Searching for insensitive melt-castable energetic materials is still facing great challenges. In this work, we developed a promising strategy that is regulating the ratio of non-covalent interaction by fluorine atoms to regulate the melting point to develop new melt-castable energetic materials. Using this method, a highly symmetric 1,2-difluoro-4,5-dinitrobenzene (DFDNB) was synthesized in one step and fully characterized. DFDNB has a desirable melting point (83.2 ​°C), high decomposition temperature (> 400 ​°C), acceptable detonation properties (6786 ​m ​s−1, 21.5 ​GPa) but superior safety performance (> 40 ​J, > 360 ​N), and excellent chemical compatibility with 1,3,5-trinitro-1,3,5-triazine (RDX) that make it a promising insensitive melt-castable energetic material. A detailed study based on crystal stacking, electrostatic potential, and intermolecular weak interactions in DFDNB and its isomers or analogs demonstrates that non-covalent interactions including the C–F⋯H, N–O⋯H hydrogen bonding, and C–F⋯O halogen-like bonding play an important role in regulating the melting point.