Azidonation derivatives of 1,1',4,4'-tetramethyl-2-tetrazene as nitrogen-rich compounds for NTO/MMH replacement - Synthesis, characterization and properties

摘要

Direct α-addition of azido groups on methyltetrazene backbones had never been described in the literature. We report herein the one-step α-azidonation of 1,1',4,4'-tetramethyl-2-tetrazene (TMTZ) that leads to 1-azidomethyl-1',4,4'-trimethyl-2-tetrazene (MATMTZ) and 1,4-di(azidomethyl)-1',4'-dimethyl-2-tetrazene (DADMTZ): two nitrogen-rich tetrazene derivatives with promising energetic interest These compounds were synthesized using azidoiodinane reagents such as the iodosylbenzene/trimethylsilyl azide couple or azidobenziodoxolone, while neither coloration reagents nor sodium azide allowed the introduction of azido groups on the α-carbon of tetramethyltetrazene. The a-azidonation reaction of TMTZ was optimized in order to predominantly form either mono- or di-azidomethyltetrazene derivative, which were characterized by ~1H, °C and ~(15)N NMR. Moreover, the theoretical heats of formation of the two azidoderivatives were computed using Density Functional Theory (B3LYF) and composite methods (CBS-QB3). Propulsion performance parameters such as density and specific impulse were calculated using, respectively, Molecular Mechanics (MM) and OPHELIE code, which is a variant of the CEA code of NASA.