摘要
采用密度泛函理论的B3LYP方法,在6-311++G**基组水平上对N8H8最稳定的环状构型分子,用等电子体-CH-基团逐个取代N原子后分别得到32种Nn(CH)8-nH8(n=0-7)的异构体,并进行了构型的优化;应用自然键轨道理论NBO和分子中的原子理论AIM分析了这些化合物成键特征和相对稳定性,G3MP2方法计算了各异构体的能量及生成热;结果表明:N原子孤对电子到相邻的碳氮键的超共轭作用是影响碳氮键长变化的主要因素;随着等电子体-CH-基团取代分子中氮原子的个数的增加,分子的生产热逐渐减小,而分子的能量将逐渐升高,且有很好的线性相关性。
With replacement of N atoms by -CH- groups one by one in the most stable ring isomer of NsH8, thirty-two possible isomers of Nn （CH） s-n Hs （ n = 0 - 7 ） have been designed amd optimized at 6-311 ＋ ＋ G ＊ ＊ level and by using B3LYP method of density functional theory. The natural bond orbital（NBO） theory and atoms in molecules （AIM） analysis are carried out to study the bonding nature and relative stabilities of these compounds. G3MP2 method is applied to calculating their energies and heats of formation. The result indicates that the hypereonjugation effect from lone pair electrons of the nitrogen atoms to adjacent C-N bonds is the major factor which caused the change of the C-N bond length. With the increase of replacement of the number of nitrogen atoms by isoeleetronic species -CH- groups, the heats of formation of the isomers decrease gradually, but the energies increase gradually and linearly.
出处
《重庆工商大学学报（自然科学版）》
2012年第5期85-91,共7页
Journal of Chongqing Technology and Business University:Natural Science Edition
基金
重庆市教委自然科学基金资助项目(09JY029-038-2)
关键词
氮氢化合物
密度泛函理论
能量
生成热
hydronitrogen compound
density functional theory （DFF）
energy
heat of formation
