Synthesis and Crystal Structure of 3-(4-Cyano-3-nitro-1<i>H</i>-pyrazol-5-yl)-4-nitrofurazan: Comparison of the Influence of the NO₂ and CN Groups on Crystal Packing and Density

Abstract

The title compound was synthesized and characterized by IR and NMR spectroscopy and single crystal X-ray diffraction. The analysis of the crystal packing of the title compound and its analog, bearing a nitro group instead of a nitrile one, allowed a direct comparison of two common explosophoric groups: CN and NO2. By using ΔOED-based densification approach, it is shown that the CN group is lighter in mass, less dense, and participates in intermolecular bonding to a lesser extent in comparison to the NO2 group. As a result, the cyano compound has a lower density and a looser crystal packing than the nitro analog.

Keywords

• energetic compounds
• pyrazole
• furazan
• single crystal X-ray diffraction
• crystal packing analysis
• quantum chemical calculations