Biomimetic Study Of Acetylacetone Dioxygenase

Acetylacetone dioxygenase can catalyze and oxidize the C-C bonds of?-diketones and convert?-diketones into carboxylic acids and oxime-ketoaldehydes.In order to get insights into the electronic effects of ligands,the electronic effects of substrates,and the influence of metal ions on the structure,properties,and molecular oxygen reactivity of acetylacetonate dioxygenase active centers,a series of studies have been conducted in this paper.The details are as follows:?1?Inthispaper,fournew3HisseriesmodelligandsL^R?Bis?2-pyridylmethyl?-R-benzylamine?:R=p-OMe,p-Me,m-Br,m-NO₂)were designed and synthesized and characterized by IR,¹H NMR and API/MS.?2?Based on S₃^R?1,3-diphenyl-propane-1,3-dione,R=OMe,Me,H,Br,NO₂?as the substrate,nine new iron ternary model complexes[Fe^IIL^RS₃^R]were designed and synthesized.and nine new nickel ternary model complexes[Ni^IIL^RS₃^R].They were characterized by IR,API/MS and CV.?3?We analyze the products of ternary model complexes reacting with molecular oxygen and obtain the degradation product benzoic acid and keto acid compounds of native enzyme.?4?Their spectroscopic features and reactivity toward dioxygen have been investigated in detail.The conclusions of our study are as follows:?1?For the iron model complex:The initial reaction rate increases with the electron-withdrawing ability of the substrate or the ligand introduced into the substituent.?2?For nickel model complexes:The initial reaction rate increases with the ability to donate electrons introduced into the substrate or ligand.?3?Metal ion effects:When the substrates are the same and the central metal ions are different,the reaction rate of the iron model complexes is faster than that of the nickel model complexes,indicating that the central metal ions have a certain influence on the enzyme activity.?4?According to a variety of spectra,kinetic data,combined with theoretical calculations,the possible reaction mechanism was inferred.