Programmatic encapsulation of hydrazine within polynitro frameworks for superior self-redox systems

The controllable storage and efficient application of hydrazine (N2H4), a vital yet hazardous chemical, remains a continuous challenge. Herein, we report a series of polynitro frameworks (PNFs), PNF-4, PNF-5, and PNF-6, that achieve molecularly precise and programmable encapsulation of four, five, and six N2H4 molecules per unit cell, respectively. This precise loading is facilitated by a structural reconfiguration of the host framework, which immobilizes guest molecules via extensive hydrogen bonds—up to 36 pairs in PNF-6. Consequently, the confined neutral N2H4 exhibits record-high thermal stability, with decomposition initiating at 201°C. Furthermore, the integration of fuel (N2H4) and oxidizer (nitro groups) creates a superior self-redox system, which enhances the propulsion performance of formulation containing PNF-6. This work provides an effective strategy for the precise, safe, and high-energy storage of N2H4 for advanced aerospace applications while also offering previously unidentified insights for integrating reactive, small molecules into adaptive frameworks for multifunctional systems.