Highly energetic tetraazidoborate anion and boron triazide adducts

The first crystal structures of the highly energetic tetraazidoborate anion and boron triazide adducts with quinoline and pyrazine as well as of tetra methylpiperidinium azide have been determined. Synthesis procedures and tho rough characterization by spectroscopic methods of these hazardous material s are given. Quantum chemical calculations were carried out for B(N-3)(4)(- ), B(N-3)(3), C5H5N .B(N-3)(3), (N-3)(3)B . NC4H4N .B(N-3)(3). and the hypo thetical C3H3N3. [B(N-3)(3)](3) at HF, MP2, and B3-LYP levels of theory. Th e structure of tetraazidoborate was optimized to S-4 symmetry and confirmed the results obtained from the X-ray diffraction analysis. The dissociation enthalpies for the pyridine (model for quinoline) as well as for the pyraz ine adduct were calculated. For pyridine-boron triazide a value of 10.0 kca l mol(-1) (for pyrazine-bis(boron triazide) an average of 2.35 kcal mol(-1) per BN unit) was obtained.