Molecular Dynamics Simulation of NTO/TNPyO Co-Crystals for Targeted Acidity Regulation of NTO

Area of Science:

• Energetic Materials Science
• Crystallography
• Computational Chemistry

Background:

• 3-Nitro-1,2,4-triazol-5-one (NTO) exhibits significant acidity (pKa = 3.76) due to facile proton dissociation, limiting its use.
• Developing noncorrosive and insensitive energetic materials is crucial for safety and broader applications.

Purpose of the Study:

• To mitigate the acidity of NTO by forming cocrystals with 2,4,6-trinitropyridine 1-oxide (TNPyO).
• To investigate the stability, mechanical properties, and detonation performance of the NTO/TNPyO cocrystal system.
• To enhance the safety and applicability of NTO-based energetic materials.

Main Methods:

• Cocrystallization of NTO and TNPyO at various stoichiometric ratios.
• Supercell modeling and simulation using Materials Studio 2023.
• Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations to analyze intermolecular forces and stability.
• Prediction of detonation performance using EXPLO-5 software.

Main Results:

• Cocrystal formation was predicted, with an optimal molar ratio of 2:1 (NTO:TNPyO).
• The cocrystal structure enhances N4-H4 bond stability, increasing the pKa by 2.8 units and significantly reducing acidity.
• Intermolecular hydrogen bonding, electrostatic interactions, dispersion, and van der Waals forces were identified as key stabilizing factors.
• The NTO/TNPyO cocrystal demonstrated potential for low sensitivity, excellent mechanical properties, and favorable detonation performance.

Conclusions:

• Cocrystallization is an effective strategy to suppress the acidity and enhance the stability of NTO.
• The NTO/TNPyO cocrystal represents a promising candidate for novel noncorrosive, insensitive energetic materials.
• This approach offers a pathway to develop safer and more versatile energetic materials for various applications.