五嗪含氮取代基衍生物结构和性质的理论研究

Theoretical Studies on Structures and Properties of Pentrazine Derivations Substituted by Substitutent Groups Containing Nitrogen

采用密度泛函理论(DFT)方法在B3LYP/aug-cc-pvDZ理论水平上研究了CN,NO2,NH2,N3,N2H,NHNH2,N4H和N4H3等含氮取代基取代五嗪环上的氢原子生成的衍生物,预测了它们的分子构型、分解能及含能性质.对衍生物分解能的研究结果表明,CN和NH2取代的衍生物的分解能比未取代时更高,而其余基团的取代使分解能降低;取代基化合物的生成热越大,取代五嗪中的氢原子后生成衍生物的生成热也越大.N4H3,NO2,H,N2H,N4H,N3和CN取代的五嗪衍生物的单位原子生成热为72.6～108.9kJ,比文献报道的三叠氮基-均三嗪的(70.2kJ)更高.对于CN,N2H,N4H3,N3和N4H取代的衍生物,其生成热为871.4～1159.3kJ?mol-1,但N4H和N4H3的分解能较小,稳定性较差.因此,N3,N2H和CN取代的衍生物可能成为高能量、低感度的含能材料.

Density functional theory at B3LYP/aug-cc-pvDZ level is applied to study the geometries, bond dissociation energies and energetic material properties of pentrazine derivatives in which hydrogen atom of pentrazine have been substituted by CN, NO2, NH2, N3, N2H, NHNH2, N4H and N4H3 groups. Compared with the parent molecules unsubstituted, derivatives substituted by CN and NH2 groups result in higher bond dissociation energies, whereas the other lead to lower ones. The studies indicated that the higher heats of formation of compounds of substituent groups possess, the higher ones of derivatives. The normalized heats of formation of these derivatives substituted by N4H3, NO2, H, N2H, N4H, N3 and CN are 72.6～108.9 kJ, which is higher than that of triazido-s-triazine （70.2 kJ） reported. For derivatives substituted by N4H, N3, N4H3, N2H and CN groups, heats of formation calculated lie in the range of 871.4～1159.3 kJ？mol-1, but de- rivatives substituted by N4H and N4H3 show low dissociation energies and relatively low stabilities. So de- rivatives substituted by N3, N2H and CN groups should be applicable as potential of high nitrogen content high energy materials （HNC-HEMs）.