Environmentally friendly high-energy MOFs: crystal structures, thermostability, insensitivity and remarkable detonation performances

An alternative method to prepare new-generation green high-energy-density materials with excellent performances has been developed on the basis of a coordination chemistry strategy. In the present work, hydrothermal reaction of Cu(II)/Cu(I) with a rigid nitrogen-rich ligand, 3-(1H-tetrazol-5-yl)-1H-triazole (H(2)tztr), led to three high-energy metal-organic frameworks (MOFs): [Cu(Htztr)(2)(H2O)(2)](n) (1), {[Cu(tztr)]center dot H2O}(n) (2) and [Cu(Htztr)](n) (3). Referring to the coordination geometry configuration of Cu(II)/Cu(I) and flexible coordination fashion of the ligand, the energies of the complexes 1-3 are gradually improved when they are structurally transformed from 1, a mononuclear structure to 2, a 3D porous MOF incorporated with guest water molecules to 3, a well-isolated layer structure. The title complexes show outstanding thermostability (T-dec = 345 degrees C for 1, 325 degrees C for 2 and 355 degrees C for 3) and low sensitivity, confirmed by experimental and theoretical characterization. Notably, complex 3 features superior detonation properties to that of known energetic MOFs.