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

Abstract

ABSTRACT:The heats of formation (HOF) have been calculated for all the 21 cubylnitrate compounds using the semiemprical molecular orbital (MO) methods (MINDO/3, MNDO, AM1, and PM3) and for 8 of 21 cubylnitrates containing 1-4 -ONO 2 groups using the density functional theory (DFT) method at the B3LYP/6-31G * level by means of designed isodesmic reactions. The cubane cage skeletons in cubylnitrate molecules have been kept in setting up isodesmic reactions to produce more accurate and reliable results. It is found that there are good linear relationships between the HOFs of the 8 cubylnitrates calculated using B3LYP/6-31G * and two semiempirical MO (PM3 and AM1) methods, and the linear correlation coefficients of PM3 and AM1 methods are 0.9901 and 0.9826, respectively. Subsequently, the accurate HOFs at B3LYP/6-31G * level of other 13 cubylnitrates containing 4-8 -ONO 2 groups are obtained by systematically correcting their PM3-calculated HOFs. Compared with noncaged nitrates, all the 21 cubylnitrates have high heats of formation implying that they may be very powerful energetic materials and have highly exploitable value. The relationship between the HOFs and the molecular structures of cubylnitrates has been discussed.

Enhanced sensitivity and stability in two‐color in situ hybridization by means of a novel chromagenic substrate combination

“…It is noteworthy that our previous studies have shown that with the number of ONO 2 groups increasing, the HOFs of noncaged nitrates and cubylnitrates decrease, all the 32 noncaged nitrates have negative HOFs 16, and all of the cubylnitrates except cubyloctanitrate have positive HOFs at the B3LYP/6‐31G* level 33. While, the HOFs of ONO 2 derivatives of HAA investigated here increase as the number of ONO 2 increases because NH 2 ONO 2 has positive HOF (40.3 kJ/mol), but the HOF of CH 3 ONO 2 is negative (−124.40 kJ/mol) 41.…”

“…It is clear that the property of group additivity of HOFs is better reflected here. In addition, one NC group can introduce the most increment of HOF due to its highest energy, which has also be testified by the HOFs of the derivatives of cubane 33–35.…”

“…To be specific, we took HAA as a reference compound when designing isodesmic reactions at the B3LYP/6‐31G* level. This method or ideal has proved reliable 8, 10, 18, 33–35.…”

Quantum chemical study on 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) and some of its constitutional isomers

“…(The parameterization of PM3 method is such that its HOF data are reliable. Moreover, it is a fast method [71][72][73][74][75][76][77].) All these data in Table 6, compared to NTO which is well known explosive, gave some clue about the explosive character of the molecules derived from NTO, so far unknown compounds in the literature.…”

Theoretical studies on new potential high energy density compounds (HEDCs) adamantyl nitrates from gas to solid

“…It is obvious from Table 2 that with the number (n) of ONO 2 groups increasing, the HOFs of these compounds decrease. This phenomenon has also been found in other 32 ONO 2 derivatives [52] and cage cubylnitrates [35] , which have the same structure of C ONO 2 that exists ONO 2 derivatives of adamantane. However, our calculations have also predicted that the HOFs of hexaazaadamantane ONO 2 derivatives, of which the ONO 2 groups are bonded to N in a form of N ONO 2 , increase with n increasing [24] .…”