Effect of Hydrogen Bond Interaction on the Decomposition Temperature, Aromaticity, and Bond Order of Nonmetallic Pentazolate Salts
Shuaijie Jiang, Qixuan Du, Yuangang Xu, Qiuhan Lin, Ming Lu, Pengcheng Wang
Abstract
Nonmetallic pentazolate (cyclo-N5–) salts are novel polynitrogen high-energy-density materials with great potential and application prospects. Hydrogen bond networks play a vital role in improving the thermal stability of these compounds. In order to further increase the decomposition temperature (Td) and attain a more thorough exploration of these compounds, we evaluated and visualized the energy of hydrogen bonds (E_HBs) and the effects of HBs on Td, aromaticity, and the Mayer bond order (MBO). The increase in the total E_HBs can increase the Td, such as with 3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazol-2-ium and biguanidinium pentazolates. Moreover, an increase in the maximum E_HBs can reduce the aromaticity of the cyclo-N5– anion and increase the difference between the maximum and minimum MBO, like 3,9-diamino-6,7-dihydro-5H-bis([1,2,4]triazolo)[4,3-e:3′,4′-g][1,2,4,5]tetrazepine-2,10- diium and O-(carboxymethyl)hydroxylammonium pentazolates. In addition, increasing the number of donors of hydrogen bonds, especially the proportion of O–H bonds, can significantly increase the Td of pentazolate salts.