A Highly Energetic N‐Rich Zeolite‐Like Metal‐Organic Framework with Excellent Air Stability and Insensitivity

A stable N‐rich aromatic ligand is employed to prepare energetic zeolite‐like metal‐organic frameworks. IFMC‐1 shows excellent air stability, and the lowest sensitivity toward impact, friction, and electrostatic discharge and the highest predicted heat of detonation among the reported coordination polymers, and even commercial materials (such as trinitrotoluene (TNT)).


S1. Materials and Measurements
The ligand H 3 dttz was synthesized according to modified procedure of the reported literature. [1] All other chemicals were obtained from commercial sources, and were used without further purification. Single crystal X-ray diffraction data were recorded on a Bruker APEXІІ CCD diffractometer with graphite-monochromated Mo Kα radiation (λ = 0.71069 Å) at 293 K. IR spectrum was performed in the range 4000-400 cm -1 using KBr pellets on an Alpha Centaurt FT/IR spectrophotometer. The X-ray powder diffraction (XRPD) data were collected on a Bruker D8 Advance diffractometer with Cu-Kα (λ = 1.5418 Å) ranging from 5 to 50º at room temperature. Thermogravimetric analysis (TGA) of the samples was recorded using a Perkin-Elmer TG-7 analyzer heated from room temperature to 800 °C under nitrogen at the heating rate of 5 °C·min −1 . Field-emission scanning electron microscopy (FE SEM) images were obtained with a XL30 ESEM FEG microscope. The N 2 sorption measurements were performed on automatic volumetric adsorption equipment (Quantachrome Autosorb-iQ).

S2. The Synthesis of H 3 dttz
A mixture of 1H-1,2,3-triazole-4,5-dicarbonitrile (11.9 g, 100 mmol), NaN 3 (26.0 g, 400 mmol), and triethylamine hydrochloride (68.8 g, 500 mmol) in 250 mL of toluene and 50 mL of methanol was heated at reflux in a 500-mL round-bottom flask for 3 days. Upon cooling to room temperature, 200 mL of an aqueous solution of NaOH (2.5 M) was added, and the mixture was stirred for 30 min. The aqueous layer was treated with ca. 140 mL of HCl (3 M) until no further white precipitate formed. The precipitate was then collected by filtration, dried in the air, and dissolved in aqueous NaOH (1 M). The resulting clear, colorless solution was titrated with diluted HCl (1 M) until the pH of the solution was 4-5. The ensuing white precipitate was washed with successive aliquots of distilled water (500 mL), methanol (300 mL), and acetone (50 mL) to afford 16.8 g (82%) of product. 13

S3. Sensitivity
Impact Sensitivity: The impact sensitivity was tested on a type 12 tooling according to "up and down" method (Bruceton method). A 2.5 kg weight was dropped from a set height onto a 20 mg sample placed on 150 grit garnet sandpaper. Each subsequent test was made at the next lower height if explosion occurred and at the next higher height if no explosion happened. 50 drops were made from different heights, and an explosion or non-explosion was recorded to determine the results. RDX was considered as a reference compound, the impact sensitivity of RDX is 7.4 J.
Friction Sensitivity: 20 mg sample was placed on a Koзπoв apparatus. 25 tests were done. An explosion or non-explosion was recorded. RDX was considered as a reference compound, and the friction sensitivity of RDX is 76%. The friction sensitivities of 1 and 2 are 0 %. Test conditions: 20 °C (temperature); 28% (relative humidity); 90° (swing angle); 474.6 MPa (test pressure).
Electrostatic Sensitivity: When electrostatic sensitivity was considered, 25 mg sample was placed on a JGY-50(Ⅲ) Electrostatic test apparatus, while the high voltage was supplied by an EST806F Electrostatic Power Generator. The voltage was increased gradually from 1 kV to 15 kV. No explosion occurred. Therefore, 25 trials were done when the voltage was 15 kV. 1 explodes at the voltage of 15 kV, while 2 shows no sensitivity to the voltage of 15 kV, which is the limit range of the apparatus. Test conditions: 25 °C (temperature); 34% (relative humidity); Capacitance: 0.22 μF.

S5. Heat of Formation
Isodesmic reaction, in which numbers of electron pairs and chemical bond types are conserved, has been employed very successfully to give heat of formation more accurate than semi-empirical calculation.
[6] Based on the optimized structures, the total energy (E 0 ) and thermodynamic parameters, including zero point energy (ZPE) and thermal correction to enthalpy (H T ), were obtained at the B3LYP/6-311++g(d, p) level. For the isodesmic reaction (Scheme S1), heat of reaction (∆H 298K ) can be calculated from the following equation (2): where ∆H f,R and ∆H f,P are the heats of formation for reactants and products at 298.15 K, respectively. Meanwhile, ∆H 298K can also be calculated using the following equation (3): ∆H 298K = ∆E 298K + ∆(PV) = ∆E 0 + ∆ZPE + ∆H T + ∆(nRT) (3) Where ∆E 0 is the change in total energy between the products and the reactants at 0 K; ∆ZPE is the difference between the zero-point energies of the products and the reactants; ∆H T is thermal correction from 0 K to 298.15 K. Since there is no change in number of total molecules, ∆(PV) = ∆(nRT) = 0. Therefore, the heat of formation can be figured out according to ∆H 298K and heats of formation of other reactants and products. Fortunately, these data can be acquired from the literature and handbook facilely.   [7] Benzene [8] -232.248647 264.51 14.00 82.9

S6. Detonation Performances
Detonation performance of the related energetic MOF (IFMC-1) here was evaluated by the empirical Kamlet formula, [9] as D = 1.01 Φ 1/2 (1+1.30ρ) P = 1.558 Φρ 2 Φ = 31.68 N(MQ) 1/2 where D represents detonation velocity (km·s -1 ) and P is detonation pressure (GPa), ρ is the density of explosive (g·cm -3 ). Φ, N, M and Q are characteristic parameters of an explosive. N is the moles of detonation gases per gram of explosive, M is the average molecular weight of these gases and Q is the heat of detonation (kcal·g -1 ). The complete detonation reactions are described by Equation (1). The formation of metal oxides as solid was assumed to be governed by the deficiency of oxygen.  Figure S1. The IR spectra of IFMC-1 measured in KBr pellets from 4000 cm -1 to 400 cm -1 . Figure S2. The TGA (left) and DSC (right) curves for IFMC-1 and H 3 dttz recorded under N 2 atmosphere from room temperature to 900 °C at the heating rate of 5 °C·min -1 . Figure S3. The temperature-dependent PXRD patterns of IFMC-1. Figure S4. The nitrogen sorption isotherms for μm-sized IFMC-1a recorded at 77 K (left) and the pore size distribution (right), respectively.