二氨基二硝基乙烯结构和性质的理论研究

对三种二氨基二硝基乙烯同分异构体进行了HF/6-31G^*^*水平、DFT-B3LYP/6-31G^*^*水平的几何全优化以及MP2/6-31G^*^*//HF-6-31G^*^*水平的总能量计算。结果表明，1,1-二氨基-2,2-二硝基乙烯(Ⅰ)总能量比顺式(Ⅱ)和反式(Ⅲ)1,2-二氨基-1,2-二硝基乙烯的总能量低，即热力学稳定性次序为Ⅰ>Ⅲ>Ⅱ。分子的共轭性和分子内氢键的强度次序为Ⅰ≈Ⅲ>Ⅱ，前沿轨道能级差次序为Ⅰ>Ⅱ>Ⅲ，也均表明(Ⅰ)最稳定。此外还计算研究了标题物的红外光谱；化合物Ⅰ的理论计算与实验值良好相符。在此基础上计算研究了标题物的热力学性质。

The theoretical study on structure and property of diamino- dinitroethylene

1,1-Diamino-2,2-dinitroethylene recently synthesized is a new energetic compound, which may be an insensitive high explosive (IHE). In this paper, the fully optimized molecular geometries and the total energies of diamino-dinitroethylene compomnds, 1,1-diamino-2,2- dinitroethylene(Ⅰ), cis(Ⅱ) and trans (Ⅲ) 1,2-diamino-1,2- dinitroethylene, have been calculated using ab initio method at the HF/6-31G^*^*, MP2/6-31G^*^*//HF/6-31G^*^* level and DFT method at B3LYP/6-31G^*^* level, respectively. The result shows that the order of stability of the title compounds is Ⅰ>Ⅲ>Ⅱ, thermodynamically. There exist strong intramolecular hydrogen bonds between nitro oxygen atoms and amino hydrogen atoms of the titled compounds and the hydrogen bond intensities of the title compounds are Ⅰ>Ⅲ>Ⅱ. Their frontier orbital energy gaps (△E) are Ⅰ>Ⅱ>Ⅲ. Based on the analysis of molecular geometry and frontier orbital component, it is found that the π-electron conjunction and delocalization of the title compounds are Ⅰ≈Ⅲ>Ⅱ. The computed vibrational frequencies of 1,1-diamino-2,2-dinitroethylene is in good agreement with the corresponding experiment results. The thermodynamic properties of DADNE were also calculated and discussed. These data are helpful to the molecular design of new IHE.