论文部分内容阅读
采用B3LYP/6-31G~(**)方法在Gaussian 03程序下,对氧杂紫菜嗪,硫杂紫菜嗪的稳定结构和能量进行优化,并寻找与内氢迁移反应相关的过渡态构型。计算结果表明,芳香性与各体系构象稳定性密切相关,但并不是决定构象稳定性的唯一因素;在中心空穴较小的紫菜嗪体系中,空间位阻,静电作用才是影响构象稳定性的关键因素。由于分子内氢键的存在,氧杂化会明显降低内氢迁移正负反应速率;而S杂化体系的IHAT速率降低则与静电斥力和空间位阻密切相关。
The B3LYP / 6-31G ~ (**) method was used to optimize the structures and energies of Oxymethazine and Omethiazine under the Gaussian 03 program, and to search for the transition state configurations related to the internal hydrogen migration. The calculated results show that the aromaticity is closely related to the conformational stability of each system, but it is not the only factor that determines the conformational stability. In the case of the zherzine system with small center hole, the steric effect is the steric stability The key factor. Due to the presence of intramolecular hydrogen bonds, oxygenation significantly reduces the positive and negative reaction rate of internal hydrogen transport. However, the decrease of IHAT rate of S hybrid system is closely related to electrostatic repulsion and steric hindrance.