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运用B3LY/6—31G(d)密度泛函理论(DFT)方法对苯并氧化呋咱、邻二亚硝基苯及其间的异构化反应进行了计算研究。结果表明,苯并氧化呋咱的分子总能量比邻二亚硝基苯的低;由苯并氧化呋咱异构为邻二亚硝基苯的正向反应活化能(Ea+=51.0KJ/mol),与文献实测值(58.6kJ/mol)较接近,而其逆向反应活化能(Ea=4.6kJ/mol)很小,从而揭示了苯并氧化呋咱比邻二亚硝基苯更稳定。此外,进行了HF/3-21G、HF/6—31G(d)和MP2/6-31G(d)//6—31G(d)水平下相应的计算,发现B3LYP-DFT的结果较abinitio为优。谐振动频率的B3LYP/6—31G(d)计算还支持了邻二亚硝基苯为苯并氧化吱咱“自-自”互变重排反应的中间体。
The B3LY / 6-31G (d) density functional theory (DFT) method was used to calculate the isomerization reaction of benzofuranoxazine, o-dinitrosobenzene and its isomers. The results showed that the total energy of benzofuranoxan was lower than that of o-dinitrosobenzene, and the activation energy (Ea + = 51.0KJ / mol) ), Which is close to the measured value (58.6 kJ / mol) and the activation energy of the reverse reaction (Ea = 4.6 kJ / mol) is small, which reveals that benzofuranoxan is more stable than o-dinitrosobenzene . In addition, the corresponding calculations were performed at the levels of HF / 3-21G, HF / 6-31G (d) and MP2 / 6-31G (d) // 6-31G (d) and found that the results of B3LYP- excellent. The B3LYP / 6-31G (d) calculation of harmonic vibrational frequencies also supports the reaction of o-dinitrosobenzene as a “self-self” interconversion rearrangement reaction of benzoxepin.