Lewis Acids Regulated Catalytic Oxidations By Diiron Complexes

The metal enzyme catalysts are well known for their ability to carry out catalytic reactions with the high efficiency,high selectivity under mild conditions.It is the goal to explore the applications of methane in the organic synthesis and industry by studying the biomimetic materials of metal enzymes like soluble methane monooxygenase?sMMO?.Due to the complicated structure of the enzymes and the poor stability,the synthetic small molecular model complexes have the strong advantage in plasticity,and it is better to understand the structures,functions,activity differences and mechanisms of the enzymes.Therefore,the study of simple complexes of enzymes has become one of the most popular topics in science and catalytic chemistry.It promotes the development of enzyme chemistry,biomimetic chemistry and other related fields.In this paper,the influences of Lewis acids on the catalytic oxidation reactions by diiron complexes with TPA or TPMA ligand.The results showed that Lewis acid like Sc³⁺could significantly accelerate the reaction rate of cyclohexane and olefin epoxidation by diiron complexs.In the absence of Lewis acid,oxidation of diiron?III?complex by TBHP would generate a well known di-?-oxo-bridged dinuclear Fe?III?Fe?IV?core which is very sluggish for C-H acitivation and olefin epoxidation.Adding non redox metal ions would cause the dissociation of the dinuclear core which sharply improves the rates of reaction.This work may offer a novel strategy to improve the catalytic reactivity of a variety of inert redox metal catalysts,and may provide new clues to understand theirs roles in catalytic oxidation mechanism of soluble methane monooxygenase.