In situ synthesized 3D heterometallic metal–organic framework (MOF) as a high-energy-density material shows high heat of detonation, good thermostability and insensitivity

Abstract

A reticular 3D heterometallic metal–organic framework (MOF), [Cu₄Na(Mtta)₅(CH₃CN)]_n (1) (N% = 40.08%), has been synthesized, using a 5-methyl tetrazole (Mtta) ligand formed from acetonitrile and azide, through in situ synthesis and structurally characterized by X-ray single crystal diffraction. The fluorescence spectra demonstrate that 1 undergoes an interesting structural transformation in aqueous solution, yielding the compound [Cu₄Na(Mtta)₅H₂O]_n (1a) as confirmed by ¹H NMR, IR and PXRD. Thermoanalysis showed that 1 possesses excellent thermostability up to 335 °C. The calculated detonation properties and the sensitivity test illustrate that compound 1 could be used as a potential explosive. In addition, the non-isothermal kinetics for 1 were studied using the Kissinger and Ozawa–Doyle methods. The enthalpy of formation was obtained from the determination of the constant-volume combustion energy.