Fused [5,7,5] Tricyclic Energetic Scaffold with a Favorable Oxygen Balance for High-Performance Explosives.

Area of Science:

• Materials Science
• Energetic Materials
• Organic Chemistry

Background:

• Ring strain in high-energy-density materials (HEDMs) can enhance detonation performance and stability.
• Current research primarily focuses on smaller, planar ring structures, limiting the potential for increased energy density.
• Larger strained rings often compromise detonation properties for stability, necessitating new synthetic strategies.

Purpose of the Study:

• To design and synthesize a novel fused [5,7,5] tricyclic energetic scaffold incorporating a strained seven-membered ring.
• To enhance detonation performance and combustion characteristics of HEDMs through structural modification and nitro group installation.
• To evaluate the sensitivity, stability, and ignition/combustion performance of the newly synthesized material.

Main Methods:

• Construction of a fused [5,7,5] tricyclic skeleton using NH-CO-NH and NH-CH2-NH bridges.
• Introduction of multiple nitro groups onto the novel fused scaffold to optimize oxygen balance and energy release.
• Computational calculation of detonation properties (velocity, pressure) and experimental evaluation of ignition delay and flame propagation.

Main Results:

• A novel fused [5,7,5] tricyclic energetic scaffold with a strained seven-membered ring was successfully synthesized.
• The hexanitro-substituted derivative exhibited a calculated detonation velocity of 9084 m/s and detonation pressure of 35.8 GPa.
• Experimental results showed significantly shorter ignition delay times and brighter flames compared to HMX and RDX, indicating superior ignition and combustion performance.

Conclusions:

• The incorporation of a strained seven-membered ring into a fused tricyclic architecture is a viable strategy for developing advanced energetic materials.
• The novel hexanitro-substituted compound demonstrates promising detonation performance, favorable sensitivity and stability, and enhanced ignition/combustion characteristics.
• This research opens new avenues for designing next-generation HEDMs with improved performance and cleaner energy release.