Stabilizing High-Energy Materials via a C–C-Connected [5,5]-Fused Triazolotriazole and Triazine Scaffold

Designing high-energy-density materials (HEDMs) with both high detonation performance and high molecular stability remains a fundamental challenge in energetic materials chemistry. Here, we report a molecular-modification strategy to balance energy output and stability through extended conjugation within a C-C-connected [5,5]-fused triazolotriazole and triazine framework. A new connected fused derivative (2), its energetic salts (3-5), and an N-oxide product (6) were synthesized and structurally characterized. The introduction of a delocalized π-conjugated scaffold, combined with extensive intermolecular hydrogen bonding, leads to an enhanced packing stability and mitigated mechanical sensitivity. These compounds exhibit high detonation velocities (up to 8808 m s⁻¹) and pressures (up to 33.0 GPa) along with low sensitivity (IS > 40 J, FS ≥ 360 N) and excellent thermal stability (Td up to 327 °C). Theoretical analyses, including Hirshfeld surface mapping, interaction region indicator (IRI), and electrostatic potential (ESP) calculations, reveal that charge delocalization and hydrogen-bond networks play a decisive role in balancing energetic performance and molecular stability.