Theoretical studies on heats of formation for polynitrocubanes using the density functional theory B3LYP method and semiempirical MO methods

Abstract

The heats of formation (HOFs) have been calculated for 21 polynitrocubane compounds using semiempirical MO methods (MINDO/3, MNDO, AM1 and PM3) and for eight of 21 polynitrocubanes containing one to four nitro groups using the density functional theory method at the B3LYP/6‐31G* level by means of designed isodesmic reactions. The cubane cage skeletons in the polynitrocubane molecules have been kept in setting up the isodesmic reactions to produce more accurate and reliable results. It is found that there is a good linear relationship between the HOFs of eight polynitrocubanes calculated using the B3LYP/6‐31G* and PM3 methods, but not for the other methods, and the linear correlation coefficient equals 0.9971. Subsequently, accurate HOFs at the B3LYP/6‐31G* level of the other 13 polynitrocubanes containing four to eight nitro groups were obtained by systematically correcting their PM3‐calculated HOFs. All 21 polynitrocubane compounds have high HOFs, implying that they can be very powerful energetic materials. The relationship between the HOFs and molecular structures for polynitrocubanes is discussed. Copyright © 2001 John Wiley & Sons, Ltd.

A review of advanced high performance, insensitive and thermally stable energetic materials emerging for military and space applications

“…In 1987, a major scientific breakthrough came in the caged polycyclic compounds, when China Lake Researchers, Nielson and co-workers synthesized the energetic solid 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12 hexaazatetracyclo (5.5.0.0 5,9 .0 3,11 ) dodecane (hexanitrohexaazaisowurtzitane (HNIW) or commonly called CL-20). HNIW is the most celebrated product of many years of research at the Naval Air Warfare Centre (NAWC) into the synthesis of novel nitramines and related energetic materials [21].…”

“…It may prove to be a more powerful explosive and/or monopropellant since it is more dense, has a calculated heat of formation only about 6% less than ONC. It will also produce some lighter gaseous products as it is not perfectly oxygen balanced [8,9].…”

“…4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo (5.5.0.0 5,9 .0 3,11 ) dodecane (TEX). It emerged out of continuing research in the design and production of explosives to provide compositions which are highly energetic when intentionally initiated but in which the risk of unintentional detonation is minimized.…”

Theoretical Studies on the Infrared Vibrational Spectra, Thermodynamic Properties and Nuclear Magnetic Resonance Spectra for Polynitro‐1,3‐bishomopentaprismanes

“…The unconspicuous discrepancies are probably due to intermolecular interactions in the experiment, which are not present in the DFT calculations applied here. As a whole, similar to the applicability of the B3LYP/6-31G* method to many substances, 7,8 it generates reliable IR spectra for PNBPP compounds.…”

“…On the other hand, there is unmatched progress in the computational modeling of IR and NMR parameters, especially by DFT methods. [7][8][9][10][11] In the present paper, the IR spectra, 13 C and 1 H NMR chemical shifts for a series of PNBPP derivatives were investigated by using DFT-B3LYP/6-31G* calculation. We hope that the computed vibrational frequencies and NMR chemical shifts of 13 C and 1 H atoms can provide references for experimentalists.…”