摘要
用MNDO法全优化了二硝基重氮酚(DDNP)和某些相关物的几何构型,计算了它们的电子结构。结果表明:DDNP在环式氧化偶氮构型下比在重氮醌型下具有较低的分子总能量;氧化偶氮五员环与苯环共平面,2号和4号位两个硝基面与苯环面之间的夹角分别约为75°和78°。综合分析比较DDNP和相关物的构型参数、原子上净电荷和^(13)C NMR谱实验,认为环式氧化偶氮型用于描述DDNP的分子结构更为合适。本文还从实验和理论上阐明了硝基与芳环间存在较大夹角是分子结构中的常见现象。
The equilibrium geometries and electronic structures of DDNP in its two structural forms and its related compounds have been optimized and calculated using the MNDO-SCF-MO method in quantum chemistry. The calculation results show that, with the cyclic azoxy configuration of DDNP, the atoms in the benzene ring and pentacyclic ring are essentially co-planar, and the dihedral angles between the benzene ring plane and the 2- and 4-nitro group planes are 75.2° and 78. 6°, respectively. The total molecular energies obtained for the 'cyclic form' and the 'quinoid form' are —3224.5723eV and —3224.3726eV respectively. Thus the former is presumably more stable than the latter. From the associative analysis and comparison of the geometric parameters and from the net charges on the atoms, as well as the observed ^(13)C NMR spectra of DDNP and its related compounds, it can be concluded that the 'cyclic azoxy form' is a rather suitable description for the molecular structure of DDNP. There is the larger dihedral angle between benzene ring and nitro group, which is the common experimental phenomenon and has been clarified with the electronic theory in this paper.
出处
《兵工学报》
EI
CAS
CSCD
北大核心
1993年第2期78-83,共6页
Acta Armamentarii
关键词
二硝基得氮酚
几何构型
电子结构
2, 4-dinitro-6-diazophenol (DDNP), MNDO method, equilibrium geometry, electronie structure
