Reaction Mechanism Of Olefin Oxidation Catalyzed By TauD-J Biomimetic Catalyst

Non heme iron oxygenase is a kind of iron oxidase which can activate dioxygen to oxidize specific biological substrate and can provide necessary substances for metabolism of organism,or realize biodegradation of organic substrate in natural environment.Therefore,it has wide application and important value in biology,environment and medicine.Mononuclear non heme iron oxygenase is one of many iron oxidases,which can participate in many important metabolic reactions.Many researchers have been devoted to the biomimetic simulation of the active center of non heme iron oxygenase.The non-heme iron complexes can catalyze many organic reactions and show strong reactivity.[Fe ^IV(O)(TQA)(NCMe)]²⁺is a biomimetic catalyst for taurine dioxygenase,and the quintet spin state is the ground spin state.In this paper,DFT was used to calculate the effect of different steric hindrance caused by different substrates on the reactivity,and the chemical selectivity between hydroxylation and epoxidation of Fe-O complexes.The results showed that for a series of substrates such as cyclobutene,cyclopentene,cyclohexene,cycloheptene and cyclooctene,the reaction energy barrier increased first and then decreased with the increase of ring,except for cyclooctene.From the reaction energy barrier,the[Fe ^IV(O)(TQA)(NCMe)]²⁺complex was more likely to undergo epoxidation,but all the products of hydroxylation reaction were more stable,so the final hydroxylation reaction was dominant.The results of the other system showed that the topological structure of the ligands and the electron donating effect of the axial ligands could affect the reaction activity.In this paper,the mechanism of trimethylphosphine oxygen transfer reaction was studied,which showed that the topological effect of ligands was due to the cis(syn)and trans(anti)of TMC ligands when supporting the Fe ^IV-O center.Axial ligand L_x=CH₃CN(AN),CF₃CO₂^-(TF),N₃^-(N3),and SR^-(SR).In addition to syn-AN.In addition to syn-AN,the influence of ligand topological structure on the reaction activity was very small.The relative activity of these compounds followed the following order:syn-AN>anti-AN;anti-TF>syn-TF;anti-N3>syn-N3;anti-SR>syn-SR.Our study also showed that the stronger the electron supplying ability of axial ligands,the lower the reaction activity was.For syn complexes,the reaction activity followed the following trend:syn-AN>syn-TF>syn-N3>syn-SR.