钴卟啉过氧中间体向环己烷夺氢的密度泛函计算

采用密度泛函理论计算方法模拟了简单钴卟啉过氧中间体PCo-O2与环己烷C6H12的作用,分析了反应路径中各驻点能量和反应过渡态分子构型。研究结果表明,PCo-O2向底物环己烷夺氢的反应可以延正方向进行,二线态PCo-O2更具反应活性,反应过程中Co-O键得到加强,O-O键被削弱。依据理论计算结果,探讨了四苯基钴卟啉催化环己烷氧化生成环己醇和环己酮的反应机理,指出反应延Lyons高价金属氧代物机理生成环己醇,而反应循环中产生的烷基自由基可以延烷基过氧化过渡金属配合物反应机理进行生成环己酮。

DFT Calculation on the Reaction of Cobalt Porphyrin Superoxide Species PCo-O2 Seizing Hydrogen Atom from the Cyclohexane Molecule

The density functional theory（DFT） calculation was performed to study the reaction of cobalt porphyrin（PCo） superoxide species PCo-O2 seizing a hydrogen atom from the cyclohexane（C6H12）. The stagnation point energies of the doublet and the quartet were analyzed to calculate the activation energy. The results supported that this reaction could be happened positively to form PCo-OOH. The doublet was confirmed to be more active on the reaction path. The steric conformations showed that the O-O bond was weakened with the formation of Co-O bond. The calculation results also suggested the mechanism of the PCo catalyzed oxidation of cyclohexane would go through with two different ways leading to produce cyclohexanol and cyclohexnone separately.