A theoretical study of 3,5-diazido-1,2,4-triazole: the role of the hydrogen bonding interaction in stabilizing the molecular system

Abstract

3,5-Diazido-1, 2, 4-triazole (DATZ) is a compound that has a good thermal stability and can be used to produce high energetic ionic salts. The conformations of DATZ were searched by the molecular dynamics simulations and optimized by the molecular mechanics and dispersion-corrected density functional theory methods. The dimer and trimer of DATZ were constructed from the most stable monomer. The hydrogen bonding interactions, which were found to be critically important in increasing the stability of the dimer and trimer, were investigated with the help of the natural bond orbital and the quantum theory of atoms in molecules analyses. The changes in thermodynamic functions, stabilization interaction energies, and hydrogen-bonding energies show that the trimer is most likely the existing form of DATZ. The intramolecular, intermolecular, and water catalytic proton transfer processes were simulated to investigate the proton transfer mechanism. The intermolecular transfer process requires the lowest activation energy (42.56 kJ mol−1) and is the most likely process of proton transfer. DATZ is not only a proton acceptor but also a proton donor. Its weak acidity was quantified as pKa = 10.16. The solvation energy estimated using the conductor-like polarizable continuum model in water is the largest (−99.96 kJ mol−1), revealing that DATZ is more stable in water than in another seven solvents.