Energetic Cocrystallization as the Most Significant Crystal Engineering Way to Create New Energetic Materials

Abstract

Crystal engineering is a highly efficient way to create new materials with the desired properties. Energetic cocrystallization has been thriving for ∼10 years since the appearance of a series of TNT-based energetic cocrystals (ECCs). ECCs serve as one important aspect of the crystal engineering of energetic materials (EMs). This article presents a brief overview of ECCs regarding the component, intermolecular interaction, packing structure, main properties, and preparation, as well as a theoretical treatment and some issues raised for future development. In most cases, the properties of an ECC are each moderated between those of the pure components, setting a basis for tuning properties by existing molecules, instead of synthesizing new molecules; meanwhile, there are also some exceptions, such as a higher density, higher detonation properties, or lower impact sensitivity in comparison with both of the pure components. These exceptions with mutated properties will expand EMs. Generally, the ECCs currently are staying at the primary stage, with much effort being required to solve some urgent issues, such as property evaluation, large-scale fabrication, and future applications. Still, energetic cocrystallization is a promising alternative to create new EMs with existing molecules; after all, it is a huge challenge to synthesize a satisfactory new energetic molecule.

Verification of the Accuracy and Efficiency of Dispersion-Corrected Density Functional Theory Methods to Describe the Lattice Structure and Energy of Energetic Cocrystals

“…Classification of the Discussed ECCs. According to our previous work, 17,18 different components and structures in ECCs cause the difference in intermolecular interaction. It is well known that the intermolecular interactions in energetic crystals are generally weak, because of the absence of strong contact sites like hydrogen bond (HB) acceptors and donors, as in CL-20-based energetic-energetic cocrystals.…”

“…As an elementary issue in ECCs, intermolecular interaction has received much attention because it roots for our understanding of molecular stacking and the derived properties and performances. − Therefore, a question arises on how we can accurately and effectively describe the intermolecular interactions in ECCs. So far, many dispersion correction schemes have been proposed for density functional theory (DFT) calculations to overcome the issue of inaccurate description of long-range interaction as the dispersion correction or the van der Walls correction. − Although a spin-component-scaled dispersion-corrected method based on second-order Møller–Plesset perturbation theory has been presented recently, corrections in DFT calculations are still the mainstream .…”

Physicochemical and thermodynamic evaluation of ibrutinib cocrystal formation with a long-chain fatty acid

“…[5][6][7][8] Cocrystallization offers great potential to address many of the material property concerns of energetic materials such as explosives, propellants, and pyrotechnics by altering the chemical stability, sensitivity to shock, and oxygen balance compared to individual components. [9][10][11] Zongwei and his coworkers generated novel energetic-energetic cocrystals composed of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HINW) and benzotrifuroxan (BTF) which is more powerful than HINW alone. 12 Utilization of cocrystals for improving pharmaceutical properties has been by far the most widely reported research category among cocrystals.…”

Preparation and crystallographic characterization of 1H-tetrazole/NaClO4 energetic cocrystal

“…In the past two decades, cocrystallization has been introduced in the field of energetic materials (Gao et al, 2017). Since then, numerous cocrystals have been created using trinitrotoluene (TNT) (Landenberger & Matzger, 2010), hexanitrohexaazaisowurtzitane (CL20) (Liu et al, 2022), and other energetic explosives (Bennion et al, 2017). These cocrystals were mainly prepared by combining two organic molecules, such as two explosive molecules, and a pair of explosive and non-explosive molecules, with the aim of decreasing the sensitivity of the parent explosives.…”