Some recent methods of encapsulating quasiporphyrin complexes into zeolite and their biomimetric oxidation catalysis were reviewed. The typical zeolite were zeolite X and Y, and mesoporous molecular sieves which cage were from 2 nm to 10 nm. The quasiporphyrin compound included metal porphyrin, phthalocyanine, salen Schiffbase, and diimine complexes. The method of encapsulation included flexible ligand route, template synthesis route, molecular impregnation route and zeolite route. The encapsulated complexes could increase turnover numbers in biomimertric oxidation. The shape and regiorelectivity, as well as reactant diffusion were controled by dimensions and shape of the environment of the active sites.
The schiff-base cobalt complex derived from tyrosine and salicylaldehyde was successfully supported on the macroporous cross-linked resin of polystyrene and obtained a new polymer-bound salen schiff base complex.This polymer catalyst was used in the aerobic oxidation of cyclohexene under mild conditions.The effects of temperature,additives and reaction time on the catalytic activity and product selectivity had also been investigated.The results indicated the allyl carbon of cyclohexene was catalytically oxidized by molecular oxygen at atmospheric pressure in the presence of the polymer complex and a trace of HOAc at 70℃,which afforded corresponding alcohol,ketone and hydroperoxide acting as intermediate.In addition,the catalytic activity is remained after being recycled 5 times.Mechanism of oxidation is a free radical reaction pathway,which is in accordance with classic Haber-Weiss radical-chain mechanism.
The microstructures of the middle-phase microemulsions were studied by using ESR and NMR techniques. The results from the two methods show that the microstructures of the middle-phase microemulsions undergo the change from O/W to bicontinuous(BC), and to W/O with the variation of NaCl concentration, and BC structure includes O/W and W/O. The models of the bicontinous structure were constructed on the base of the studies.
The penta dentate Schiff base nickel complex was encapsulated in the zeolite(NaX 13) by the flexible ligand route.Its catalytic activity in the oxidation of styrene to phenyl aldehyde by molecular oxygen was studied,which showed high activity.
