Theoretical study on structure and properties of B2Hm(NO2)n(m=2-5;n=1-4)

This paper conducts theoretical research of B2Hm (NO2) n (m = 2-5; n = 1-4) with density functional theory, determines the most stable structure through structural optimization and frequency analysis, and calculates enthalpy of formation by applying atomization reaction method and isodesmic reaction method for the most stable structure, calculates molar volume, theoretical density and explosion heat of B2Hm (NO2) n (m = 2-5; n = 1-4) at B3LYP / 6-31G * level, and studies detonation velocity, detonation pressure and other thermodynamic properties with K -J empirical formulas. Studies show that explosion heat of B2H3(NO2)(3), B2H2(NO2)(4) are1.34KJ / mol and 0.85KJ / mol respectively, less than 1.37KJ / mol of conventional explosive TNT; explosion heat of B2H5NO2 and B2H4(NO2)(2) are 1.83KJ / mol and 1.57KJ / mol, greater than that of TNT explosion heat; detonation velocity and pressure of adding compound B2Hm(NO2)(n)(m=2-5;n=1-4) more and more approach TNT as substituting cardinal number increases; Delta Egap of titled compound are 5.94eV, 5.76eV, 5.10eV and 4.76eV respectively, showing that as nitro substituent increases, Delta Egap value decreases. In Wiberg bond order analysis, B-NO2 bond is relatively weak in B2Hm(NO2)(n)(m=2-5;n=1-4) molecule, probably pyrolysis or detonation trigger bond of titled compound.