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采用密度泛函理论的B3LYP方法在6-311++G~(**)基组水平上优化了,用等电子体-CH-基团逐个取代N8H8环状异构体中最稳定的分子构型中的N原子,得到32种N_n(CH)_(8-n)H_8(n=0-7)的异构体,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。研究结果表明: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。
The B3LYP method using density functional theory was optimized at the level of 6-311 ++ G ~ (**) based on the substitution of the most stable molecular structure of the N8H8 ring isomers one by one with an iso-CH- group (N = 0-7) isomers of 32 N_n (CH) _ (8-n) H_8 were synthesized and their structures were characterized by using the theory of natural bond orbital theory NBO and atomic theory AIM Bond characteristics and relative stability, G3MP2 method to calculate the energy and heat of each isomer. The results show that the superconjugation of the lone pair electron of N atom to the adjacent carbon-nitrogen bond is the main factor affecting the change of carbon-nitrogen bond length. With the substitution of -CH- group for the number of nitrogen atoms in the molecule The molecular heat of production will gradually decrease, and the molecular energy will gradually increase with a good linear correlation.