Studies On The Metal Complexes And Their Metallomicelles As The Mimics Of Hydrolase And Peroxidase

The study of natural enzyme aroused the concern of both chemists and biologists because of its high selectivity, catalytic activity and mild reaction condition in chemical reaction. Various simple or complicated chemical systems have been used as mimic models for natural enzymes. Through investigating mimic enzyme, the mechanism of the enzymatic catalytic reaction and the correlation between the structure, property and function of the enzyme were explored, which should lay a theoretic foundation for designing and synthesizing the catalyst of simple structure, high selectivity, high catalytic activity and mild reaction condition in the chemical reaction; and should be favorable to develop green catalyst with practical value.The catalytic action of various kinds of functional coordination compound and metallomicelles which are made from the complex and micelle, as mimic hydrolase or peroxidase, have been studied respectively in catalyzing the carboxylic ester and phosphatic diester hydrolysis, and the phenolic derivant oxidation in this paper. Some novel results of academic significance have been obtained.The Schiff base transitional metal complexes of various structures as hydrolase models for the catalytic hydrolysis of PNPP and BNPP have been conducted. The kinetics of PNPP and BNPP hydrolysis catalyzed by above complexes and their metallomicelles in buffer and micellar solution has been investigated. A novel kinetic mathematical model for the reactions has been built. The proposed reaction mechanism has also been discussed. The results indicate that: (1)the hydrated complex may be real active species in the PNPP and BNPPcatalytic hydrolysis reactions; (2) the catalytic activity of crown ether substituted complexes is much higher than that of crown- free analogues in the hydrolysis of PNPP and BNPP. The crown ethers can conduce to the molecule of hydrophobic PNPP coming easily into the active center of complexes and synergize the central metal ion to activate the coordinated water molecule by the hydrogen bond formation; (3) the structure of the crown ether pendant has a certain effect on the catalytic activity of complexes and their metallomicelles. That is, the size, composition, structure and property of the crown ether pendant have an important influence on the catalytic activity of the metal complexes and metallomicelles; (4) the catalytic activity of the complex is correlated to Lewis acidity of its central metal ion, the stronger the Lewis acidity of the central metal ion is, the higher the catalytic activities of the complex is, so the order of the catalytic activity of different metal ions in the complexs is Ni(II) > Cu (II) > Co (II); (5)the activity of the mimic enzymes catalyzing PNPP and BNPP hydrolysis increases along with the increase of substrate concentration and the pH value of reaction medium, as well as the reaction temperature in a certain range.The Schiff base transitional metal complexes of various structures and their metallomicelles as peroxidase models for the phenol and phenolic derivant oxidation have been investigated. Some results are obtained from the studies: (1) the Schiff base transitional metal complexes have high catalytic activity for the phenol and phenolic derivant oxidation, and the structure of the complexes has a great effect on its catalytic activity; (2)a novel kinetic mathematical model for the complexes and their metallomicelles catalyzing the phenolic derivant oxidation has been established; (3) the feasibility and mechanism for the phenolic derivant oxidation catalyzed by the metallomicelle(as the mimetic model of peroxidase)have been discussed.The new results obtained from above studies with the various kinds of the metal complexes and their metallomicelles is to simulate the hydrolase and peroxidase, provide valuable information and foundation for designing higher active mimic hydrolase and peroxidase and to investigate the catalytic mechanism of the simulated enzymes.