Synthesis, Characterization And Catalysis Mechanism Of Transition Metal Complexes With Di(2-Picolyl)amine Derivatives

Under mild conditions,the bio-inspired catalysts based on non-heme oxygenases can catalyze oxidation of a large range of substrate such as alkanes,alkenes and phenols,selectively and efficiently.It may give a promising way to develop the green oxidation process.In recent years, the development of biomimetic model systems has led to exciting breakthrough in the field of non-heme oxygenases.Twelve new transition metal complexs of a di(2-picoly)amine derivatives were synthesized as functional models of non-heme oxygenases,their catalytic properties for the oxidation of toluene were investigated exhaustively.The oxidation for methyl group of toluene catalyzed by the complexs were studied. Specific results are as follows:1.Result shows that the copper catalysts show higher activity,which is probably related to the coordination of the acetate groups,two labile sites of coordination and the coordination of the different ions.Experimental data shows that the different cocatalysts can increase the yields of oxide or the selectivity of products,and appropriate amount of alkali can increase conversion rate of oxidation products.The mononuclear copper perchlorate complex exhibited higher chemo-selectivity in ligand benzylation.A new compound N-benzyl-2-benzyl-bis(pyridylmethyl)amine was produced and the reaction of benzylation mechanism was speculated.This is the first report internationally.2.A new manganese complex of N-benzyl-bis(pyridylmethyl)amine can form a Mn-OOH adduct with hydrogen peroxide,which can hydroxylize itself and produce a new hydroxylated compound.3.A Mn(â…¢) peroxo intermediate was found firstly using UV-vis spectrum in the low temperature.A mechanism involving an peroxomanganese intermediate prior to C-H bond activation was proposed.Prior cleavage of the peroxo O-O bond would form a transient high diperoxomanganese oxidant that transfers one of the four oxygen atoms to the ligand.4.Hydrogen peroxide has a great impact on the selectivity of the oxidation products.Excess hydrogen peroxide led the formation of iron-catalyst-H₂O₂ complexes which produce hydroxyl radicals producing long-lived alkyl radicals-a powerful and nonselectivies oxidant for toluene.When hydrogen peroxide content is low, iron-catalyst-H₂O₂ combines with toluene generate a metal-based oxidant that generates short-lived alkyl radicals and increases the selectivity of the oxidation of toluene.