Prediction of energetic properties of carboranyl tetrazoles based on DFT study

Abstract

Compounds which are rich in boron and nitrogen have the potential to find application as high-energy material. In the present article quantum-chemical calculations (DFT B3LYP/6-311 + G*) of geometric and electronic structures, enthalpies of formation, highest occupied and lowest unoccupied molecular orbital (HOMO and LUMO) energies and the detonation properties of 22 molecules of carboranyl tetrazoles were carried out. The method of the estimation of enthalpies of formation of carboranyl tetrazoles based on full energies of the molecules and semi empirical parameters for solid carbon (graphite) and boron was proposed. The enthalpies of formation of carboranyl tetrazoles were evaluated. Theoretical terahertz frequencies for potential high-energy density materials (HEDMs) were computed which allows the opportunity for the remote detection of these compounds. According to the results of calculations the most promising HEDMs among studied compounds were found to be 9,12-bis(2-(5-phenyl-tetrazol-2-yl)propyl)-o-carborane; 9,10-bis(2-(5-phenyl-tetrazol-2-yl)propyl)-m-carborane; 5,5’-(butan-1,4-diyl)-{9,12-bis[2-(tetrazol-2-yl)prop-1-yl]-о-carborane}. Based on the calculated frontier molecular orbital energy gap these energetic materials are even less impact sensitive than classical diaminotrinitrobenzene (DATB) and trinitroaniline (TNA). These compounds are characterized by the maxima magnitudes of the evaluation of the enthalpies of formation (EOF) and can be considered as promising HEDMs as their EOF values are notably higher than those of well-known trinitrotoluene (TNT) and hexogen (RDX, Research Department eXplosive).