Crystal structures, thermodynamics and accelerating thermal decomposition of RDX: two new energetic coordination polymers based on a Y-shaped ligand of tris(5-aminotetrazole)triazine

Abstract

Based on a flexible Y-shaped energetic ligand, tris(5-aminotetrazole)triazine (H₃TATT), two new energetic coordination polymers (ECPs), {[Zn₂(HTATT)₂(H₂O)₂]·3H₂O}_n (1) and [PbZn(TATT)(OH)(H₂O)]_n (2), have been synthesized under hydrothermal conditions. X-ray single crystal structure analysis shows that both 1 and 2 are 1D chain structures. Different from 1, a large number of hydrogen bond interactions in 2 expand it into a 3D supramolecular configuration. The theoretical density and thermal stability of 2 are higher than 1. The experimental values of molar heat capacities of 1 and 2 in the temperature range of 293.15 K–368.15 K are measured by using a DSC instrument and fitted to a polynomial equation of heat capacities by the least squares method. Smoothed heat capacities and thermodynamic functions of 1 and 2 relative to the standard reference temperature 298.15 K were derived from the fitted polynomial equation. In addition, the theoretical estimation results show that 1 and 2 possess good detonation velocity and detonation pressure. Sensitivity tests indicate that 1 and 2 are insensitive to impact and friction stimuli. Furthermore, 1 and 2 were explored as combustion promoters to accelerate the thermal decomposition of RDX (1,3,5-trinitro-1,3,5-triazinane) by differential scanning calorimetry.