Theoretical Screening of Novel 5-picrylamino- 1,2,3,4-tetrazole (PAT) and 5,5′-styphnylamino-1,2,3,4-tetrazole (SAT) Derivatives: A New Molecular Design Strategy of Multi-Nitrogen Energetic Materials by Introducing Intermolecular Hydrogen Bonds and π–π Stacking Interactions

ABSTRACT

On the basis of a design strategy that results in the introduction of intramolecular hydrogen-bonds and π–π stacking interactions leading to low-sensitive and high-energy materials (LSHMs), –NH₂/–NO₂ fused derivatives of 5-picrylamino- 1,2,3,4-tetrazole (PAT) and 5,5′-styphnylamino- 1,2,3,4-tetrazole (SAT) were designed and investigated theoretically. Density functional theory has been explored to investigate the geometric, electronic structures, band gaps, and heats of formation. The detonation performance was evaluated by using Kamlet-Jacobs equations based on the calculated densities and enthalpy of formation (EOF). The thermal stability of these compounds was studied by calculating bond dissociation energies and energy gaps. Proper numbers of 5-aminotetrazole (5-AT) moieties can enhance the EOFs of explosives, further improving the detonation performance as well as nitro group. Though introducing more nitro-groups into TATB frameworks, NH-moieties can retain the intramolecular hydrogen-bond, which can enhance the crystal-packing and physico-chemical stability. Meanwhile, noncovalent interaction (NCI) plots reflects that intermolecular interaction also has a crucial influence on the mechanical sensitivity for the designed derivatives, except for the energy gap (ΔE) and bond dissociation energy (BDE). UV/Vis spectra and ¹⁵N isotropic magnetic shielding were further computed for characterizing and predicting the molecular structure and reaction mechanism towards the future experiments. The predicted performance implies that the designed molecules are expected to be promising candidates for multi-nitrogen energetic materials.

KEYWORDS:

• aromatic energetic materials
• intermolecular interaction
• molecular design

Acknowledgments

The first author also thanks to Prof. Bisheng Tan, Dr. Qun Zeng, Xiujuan Qi, and Huarong Li for their useful discussions.

Funding

We are grateful for the financial support from the National Natural Science Foundation of China (NSFC, Grant Nos. 11402237, 21172203 and 11302200), and the Science and Technology Fund of CAEP (2015B0302055).