螺环化合物环应力、生成热及重排机理的理论研究

【作者】 袁烺；

【导师】 李丽；

【作者基本信息】 黑龙江大学 ， 环境科学， 2010， 硕士

【摘要】 本文采用密度泛函方法对所选螺环化合物环应力、生成热及重排机理进行了理论研究。研究主要针对1-亚甲基-2-乙烯基环丙烷、3-亚甲基环戊烯、1-亚环丙基-2-乙烯基环丙烷和4-亚甲基螺[2,4]庚-5-烯体系进行了探讨。采用键反应模型对相关体系的环应力进行了计算,结果表明,在B3LYP/6-311G(d,p)水平下采用超同键模型,所计算出来的环应力值与实验值吻合较好。可以预测螺环化合物的结构中若含有环烯烃结构,环应力则随着环的数目增多而减小,稳定性也随之增强。采用了12种方法对相关体系的生成热进行计算,通过与实验值作对比,结果表明,在所选的12种方法中B3LYP/6-311 G(d,p)、B3LYP/6-311++G(d,p)和B3LYP/6-311++ G(2df,2p)这三种方法计算出来生成热值接近于实验值,其中采用B3LYP/6-311++G( 2df,2p)方法计算出来生成热值与实验值吻合最好。通过对目标体系重排机理的计算,结果表明,反应1-亚甲基-2-乙烯基环丙烷到3-亚甲基环戊烯,反应1-亚环丙基-2-乙烯基环丙烷到4-亚甲基螺[2,4]庚-5-烯的重排均是一步完成的。更多还原

【Abstract】 The ring strain energies, heats of formation and rearrangement mechanism of the selected spiro-compounds were investigated by using DFT methods. In this thesis, we systematically studied the 1-Methylene-2-vinylcyclopropane,3-methylenecyclopentene, 1-cyclopropylidene-2-vinylcyclopropane and 4-methylenespiro[2,4]hept-5-ene systems. The reaction models were employed to calculate the ring strain energies of the selected systems. The computational results indicated that the ring strain energies of the systems which were computed at the B3LYP/6-311G(d,p) level by using the Hyperhomodesmotic model have good agreements with the experimental values. We have a prediction that if the structure of the spiro-compounds contains the cycloalkene, the ring strain energy declines with increasing ring number, and while the stability of the system also increases. Twelve methods were used to compute the formation heat of the system. By comparison with the experimental values, among the 12 methods, the computational results indicated that the formation heat of the system calculated by the B3LYP/6-311G(d,p), B3LYP/6-311++G(d,p), and B3LYP/6-311++G(2df,2p) methods are more close to the experimental values, and the computational results coming from the B3LYP/6-311++G(2df,2p) method has the best agreement with the experimental values among the three methods. According to the results, we can also know that the rearrangements of 1-Methylene-2-vinylcyclopropane to 3-methylenecyclopentene, 1-cyclopropylidene-2-vinylcyclopropane to 4-methylenespiro[2,4]hept-5-ene are single-step channels.更多还原