N3H5异构化及构象分析

Isomerization and Conformation Transformation of Triazane

采用量子化学的方法,对氮氢化合物N3H5所有可能的二面角变化进行松散势能面扫描,获得了相应的能量和构象之间的关系,研究了N3H5的异构化机理和构象的变化.分子中的原子(AIM))理论计算得到的键临界点电荷密度的增大和减小,及其拉普拉斯值的正负变化,可以清楚地反映构象转化过程中键的增长、断裂和新键生成的相关信息.自然键轨道(NBO)理论分析表明,立体排斥作用使分子能量升高,而超共轭作用使分子能量降低,它们对分子构象的相对稳定性起了重要作用.

Isomerization mechanism and conformation transformation of triazane were studied by quantum chemistry computation. The relationship between the energy and the conformation was obtained by a relaxed scan for all possible dihedral angles of triazane. By means of atoms in molecules （AIM） computation, the increase and decrease of the charge density of bond critical point and the positive and negative variation of its Laplace value induced by conformation can be obtained, which may provide clear information for the change, break, and formation of the nitrogen-nitrogen or nitrogen-hydrogen bond. Nature bond orbital （NBO） analysis revealed that the energy of isomer was increased by the steric effects, and it is decreased by the hyperconjugation effects. The relative stabilities of isomers can be attributed to the steric and hyperconjugation effects.