Mechanistic Insight Into Decomposition Of Metalloporphyrin By Fluorescent Probe And Synthesis Of TEMPO-Porphyrin

Iron(III) porphyrin, as a biomimetic model of cytochrome P450, has been widely used in biomimetic catalysis,organic synthesis and other fields. The author synthesized two kinds of metalloporphyrin TPPFeCl and TCPPFeCl, researching cyclohexene oxidation by H2O2 catalyzed by metalloporphyrin.Based on this reaction, we explore degradation mechanism of TCPPFeCl in the process of catalytic oxidation.Metalloporphyrin catalyst occured decomposition situation in the process of catalyzing cyclohexene oxidated by hydrogen peroxide, this caused inactivation of catalyst and affected its catalytic activity. This paper synthetized a new fluorescent probe TEMPO-BODIPY and confirmed its fluorescence selectivity of testing hydroxyl free radical. We used the probe directly exploring the reaction process of TCPPFeCl catalyzing hydrogen peroxide oxidating cyclohexene. This res?lts were a large enhancement in fluorescence intensity and recover of BODIPY fluorochrome. In addition, both the reaction process of TCPPFeCl catalyzing hydrogen peroxide oxidating cyclohexene and process of TCPPFeCl reacted with Fenton were on-line monitored by UV-Vis. The result was that metalloporphyrin catalyst also decomposed. Therefore, we could conclude that hydroxyl free radical was one of principal factors to cause the decomposition of metalloporphyrin catalyst in the process of TCPPFeCl catalyzing hydrogen peroxide oxidating cyclohexene.How to solve the problem of metalloporphyrin catalyst's decomposition in the process of oxidating cyclohexene by hydrogen peroxide catalyzed by TCPPFeCl was the key of that metalloporphyrin catalyst can be reused or not. At present, most approachs to reducing metalloporphyrin degradation and promoting catalyst stability were immobilizating catalyst on supporting earrier. However, this researchs were formed modifing molec?lar structure of metalloporphyrin. We synthesized a new TEMPO-Porphyrin putting the Tempo oxynitride "grafting" on the ? aromatic ring of metalloporphyrin to protect the catalyst from decomposition. Compared the catalytic performance of TCPPFeCl and TEMPO-Porphyrin in the reaction process of oxidating DBS by hydrogen peroxide. The decomposition situation of metalloporphyrin catalyst was on-line monitored by UV-Vis. The result was that the decomposition rate of new TEMPO-Porphyrin was smaller than that of TCPPFeCl. However, it did not stop completely the decomposition. The new porphyrin could reduce the decomposition rate of porphyrin catalyst to a certain extent. We provided merely a new idea of solving the decomposition of metalloporphyrin.