金属四苯基卟啉-次氯酸钠模拟体系中芳醛氧化反应的研究

Oxygenation of Aromatic Aldehydes by the Metallotetraphenylporphyrin-Sodium Hypochlorite System

金属卟啉作为催化剂已在生物模拟氧化和自动氧化反应中获广泛应用。细胞色素P450单加氧酶模拟体系中,烷烃羟基化和烯烃环氧化研究已有大量文献报道。有关反应机理研究表明,高价金属卟啉含氧活性中间体(O=MPor·)的形成是反应的关键步骤。我们前文研究了在金属四苯基卟啉存在下,用分子氧氧化芳醛的过程。

In this work, the catalytic behaviours of Mn(Ⅲ)-porphyrin in the oxidation of aromaticaldehydes with NaOCl as oxidant under two-phase condition have been investigated. When TPPMn(Ⅲ)OAc, TPPFe(Ⅲ)Cl, TPPCo(Ⅱ), and TPPNi(Ⅱ) were used as catalysts, only TPPMn(Ⅲ)OAcand TPPFeCl exhibit distinct activites. With TPPMn(Ⅲ)OAc as catalyst. UV-visible spectralchanges of the fourth band from 425nm to 478nm were observed during the course of the oxygentransfer, suggesting that oxo-manganese (v) porphyrin is the key element for the oxygenation of aldehydes. It was found that electron withdrawing p substituents of TPPMnOAc lead to an in-crease in activities and stabilities. Electron withdrawing ortho substituents increase the stabilities ofmanganeseporphyrins, but decrease their activities. Of the metalloporphyrins tested, T_(DC) PPMnOAcwas found to be the most stable one with higher activity.