Theoretical study on intermolecular interactions of 3-nitro-1 2,4-triazol-5-one with NH3 and H2O

Five fully optimized geometries of 3-nitro- 1,2,4-triazol-5-one (NTO)/NH3 and NTO/H2O supermolecules have been obtained with density functional theory method at the B3LYP/6-311++G(**) level. The intermolecular interaction energy was calculated with basis set superposition error correction and zero point energy correction. The greatest corrected intermolecular interaction energies of the NTO/NH3 and NTO/H2O supermolecules are -37.58 and -30.14 kJ/mol respectively, indicating that the intensity of interaction between NTO and NH3 is stronger than between NTO and H2O. Electrons in supermolecular systems transfer from NH3 or H2O to NTO. The strong hydrogen bonds contribute to the interaction energies dominantly. Natural bond orbital (NBO) analysis was performed to reveal the origin of the interaction. Based on the vibrational analysis, the changes of thermodynamic properties from the monomer to supermolecules with the temperature ranging from 200.0 to 800.0 K have been obtained using the statistical thermodynamic method. It was found that structures II and III can be produced spontaneously from NTO and NH3 at room temperature, while structures IV, V and VI can only be produced spontaneously from NTO and H2O at lower temperature.