Poly Tetrazole Containing Thermally Stable and Insensitive Alkali Metal-Based 3D Energetic Metal-Organic Frameworks

Twonovel energetic EMOFs, [Na-3(L)(3)(H2O)(6)]( n ) (1) and[K-3(L)(3)(H2O)(3)]( n ) (2), with the self-assemblyof the L3- ligand with alkali metals Na-(I) and K-(I)were prepared at ambient conditions from 1,3,5-tris-((2H-tetrazol-5-yl)-methyl)-1,3,5-triazinane-2,4,6-trione (TTzTA) ligand with NaOH and KOH in water. Both compounds 1 and 2 show excellent thermal decomposition T (d) = 344 and 337 degrees C, respectively, comparedto the presently used benchmark explosives RDX (210 degrees C), HMX(279 degrees C), and HNS (318 degrees C), which is attributed to structuralreinforcement induced by extensive coordination. They also show remarkabledetonation performance and insensitivity toward impact and friction.Their excellent synthetic feasibility and energetic performance suggestthat they are the perfect blend for the replacement of present benchmarkexplosives, such as HNS, RDX, and HMX. Polytetrazole-containing thermally stable and insensitive alkalimetal-based 3D energetic metal-organic frameworks (EMOFs) arepromising high energy density materials to balance the sensitivity,stability, and detonation performance of explosives in defense, space,and civilian applications. Herein, the self-assembly of L3- ligand with alkali metals Na-(I) and K-(I) was prepared at ambientconditions, introducing two new EMOFs, [Na-3(L)(3)(H2O)(6)]( n ) (1) and [K-3(L)(3)(H2O)(3)]( n ) (2). Single crystal analysisreveals that Na-MOF (1) exhibited a 3D wave-like supramolecularstructure with significant hydrogen bonding among the layers, while K-MOF (2) also featured a 3D framework. Both EMOFs were thoroughlycharacterized by NMR, IR, PXRD, and TGA/DSC analyses. Compounds 1 and 2 show excellent thermal decomposition T (d) = 344 and 337 degrees C, respectively, comparedto the presently used benchmark explosives RDX (210 degrees C), HMX(279 degrees C), and HNS (318 degrees C), which is attributed to structuralreinforcement induced by extensive coordination. They also show remarkabledetonation performance (VOD = 8500 m s(-1), 7320 ms(-1), DP = 26.74 GPa, 20 GPa for 1 and 2, respectively) and insensitivity toward impact and friction(IS >= 40 J, FS >= 360 N for 1; IS >= 40 J, FS >= 360 N for 2). Their excellent syntheticfeasibility and energetic performance suggest that they are the perfectblend for the replacement of present benchmark explosives such asHNS, RDX, and HMX.