Computational study of nitrogen-rich hexaazaadamantane cage compounds as potential energetic materials

Abstract

Context

Nitrogen-rich carbocyclic cage compounds serve as versatile platforms for the design and development of explosives with tailored properties. Their compact and rigid structure due to efficient packing leads to high crystal density. Moreover, their structural characteristics and amenability to functionalization make them indispensable in the quest for more powerful and efficient energetic materials. Adamantane derivatives are promising candidates for high-energy materials due to their unique molecular structure and the ability to introduce explosophoric groups onto their scaffold. In this computational study, we investigated the effects of substitution of six different explosophoric groups on the hexaazaadamantane skeleton. We explore the incorporation of − N(O)− NNO₂, − N(O)− NCN, − N₃, − ONO₂ − NO₂, and − NH₂ functionalities, renowned for their high-energy content and ability to enhance explosive properties. We predict the electronic structure, heat of formation, thermodynamic stability, impact sensitivity, and detonation performance of these azaadamantane derivatives. The results indicate that the nitrogen-rich adamantane-based cage structure, featuring − ONO₂ functional groups along with − NH₂ groups, exhibits excellent explosive properties and good impact sensitivity. Our computational approach enables the screening and design of novel energetic materials with superior explosive properties, offering insights into structural modifications that optimize energy release, sensitivity, and detonation characteristics.

Methods

Density functional theory (DFT) using the Gaussian 16 software was used for all quantum chemical calculations. The optimization of the geometry of the designed compounds is performed at two different levels, e.g., B3LYP/6–311 + + G(d,p) and B3PW91/6-31G(d,p). Molecular surface and other properties are visualized using the Gaussview 6.0 software. The heat of formation (HOF) of the molecules is estimated using isodesmic reactions. The Multiwfn program was used for the calculation of molecular surface properties.