2,2′-Azobis(1,5′-bitetrazole) with a N10 Chain and 1,5′-Bitetrazolate-2N-oxides: Construction of Highly Energetic Nitrogen-Rich Materials Based on C–N-Linked Tetrazoles

A series of high-nitrogen compounds, including a unique molecule 2,2′-azobis(1,5′-bitetrazole) with a branched N 10 chain and 1,5′-bitetrazolate-2 N -oxides, were synthesized successfully based on C–N-linked 1,5′-bistetrazoles using azo coupling of N -amine bonds and N -oxide introduction strategies. All compounds were characterized by NMR spectroscopy, IR spectroscopy, elemental analysis, and differential scanning calorimetry, in which the structures of five compounds were further determined by single-crystal X-ray diffraction analysis ( 2, T-N10B, 3a, 3b, and THX ). The nitrogen contents of these five compounds range from 63.62 ( THX ) to 83.43% ( T-N10B ), which are much higher than that of CL-20 (38.34%). The heat of formation for the prepared compounds was calculated by using the Gaussian 09 program, with T-N10B having the highest value of 5.13 kJ g –1, about 6 times higher than that of CL-20 (0.83 kJ g –1 ). The calculated detonation performances by EXPLO5 v6.05.04 show that THX has excellent detonation performance ( D = 9581 m s –1, P = 35.93 GPa) and a remarkable specific impulse ( I sp = 284.9 s).