Isosteric Substitution Enables Rational Design of Two-Dimensional Energetic Crystals.

Area of Science:

• Materials Science
• Chemical Engineering
• Crystallography

Background:

• Two-dimensional (2D) energetic crystals offer unique properties but have limited molecular design options.
• Current designs primarily rely on the "NH2-C-C-NO2" motif, restricting innovation.
• Interlayer slip is the main mechanism for energy dissipation in 2D energetic crystals.

Purpose of the Study:

• To expand the molecular design space for 2D energetic crystals.
• To introduce a functional group isosterism substitution strategy using the aminofurazan unit.
• To co-optimize energy output and safety in novel energetic materials.

Main Methods:

• Database mining and high-throughput enumeration to generate candidate molecules.
• A tiered screening process involving virtual assessment and cross-scale stability evaluation.
• Synthesis and structural confirmation of high-priority target compounds.

Main Results:

• Identified and synthesized two novel 2D energetic crystals (compounds 3 and 12).
• Both materials exhibit high thermal stability, low mechanical sensitivity, and strong detonation performance.
• Compound 12 surpasses TATB in detonation velocity, temperature, and heat of detonation while maintaining low sensitivity.

Conclusions:

• The aminofurazan unit is a versatile building block for designing advanced 2D energetic crystals.
• The functional group isosterism strategy effectively balances high energy with low sensitivity.
• This approach provides a blueprint for developing next-generation low-sensitivity energetic materials.