Structure and properties of pentazole ionic salts

Area of Science:

• Computational chemistry
• Materials science
• Energetic materials

Background:

• Investigated 13 anhydrous pentazole non-metallic ionic salts (PA-1 to PA-13).
• Compared properties against established energetic materials like TNT and RDX.
• Utilized periodic density functional theory for systematic analysis.

Purpose of the Study:

• To systematically study the properties of 13 anhydrous pentazole ionic salts.
• To evaluate their potential as high-energy materials.
• To understand the structure-property relationships, particularly the influence of cation substituents.

Main Methods:

• Employed density functional theory (DFT) calculations using Gaussian 16.
• Optimized structures using B3LYP-D3/6-311G**.
• Performed single-point energy calculations using M06-2X-D3/def2-TZVPP.

Main Results:

• Pentazole ionic salts (PA-1 to PA-13) showed higher heats of formation than TNT and RDX.
• PA-9 demonstrated exceptional detonation performance (9.41 km/s) and heat of formation (1357.56 kJ/mol).
• Cation substituents like -NH2 and -OH improved energy and performance, while -COOH decreased them. -OH enhanced reactivity over -NH2, and increased -NH2 or carbonyl groups reduced it.

Conclusions:

• Pentazole ionic salts, particularly PA-9, show significant potential as next-generation high-energy materials.
• Cation design is crucial for tuning energetic properties and stability.
• -NH2 and -OH substituents are beneficial for enhancing performance, while cation size impacts sensitivity and stability.