A green high-initiation-power primary explosive: synthesis, 3D structure and energetic properties of dipotassium 3,4-bis(3-dinitromethylfurazan-4-oxy)furazan

Abstract

A new green primary explosive, dipotassium 3,4-bis(3-dinitromethylfurazan-4-oxy)furazan (K₂BDFOF), was synthesized via a four-step procedure including cyano addition, diazotization, N₂O₅ nitration, and KI reduction. The compound was characterized by multinuclear NMR spectroscopy, IR spectroscopy, elemental analysis, DSC, TG/DTG as well as single crystal X-ray diffraction. X-ray diffraction studies reveal an intriguing 3D framework structure. The central K ions are linked by dinitromethanide anions to give a 1D spiral chain with parallelogram-like repeat units, and these 1D chains are further linked by one oxygen atom in the nitro group coordinated with a K ion to form a two-dimensional wave-like layer structure. Additionally the kinetic parameters of the exothermic process for K₂BDFOF were studied by Kissinger's and Ozawa–Doyle's methods. The sensitivities were determined by standardised impact and friction tests, and the heat of formation was calculated with the atomization method at the CBS-4M level of theory. With the heat of formation (−8.4 kJ mol⁻¹) and the room-temperature X-ray density (2.09 g cm⁻³), impressive values for the detonation parameters such as detonation velocity (8431 m s⁻¹) and pressure (329 kbar) were computed using the EXPLO5 program and compared to the most commonly used primary explosive, lead azide, as well as the recently published dipotassium 1,1′-dinitramino-5,5′-bistetrazolate.