Synthesis and catalytic capability of metalloporphyrins encapsulated in molecular sieve supercages

A stepwise synthesis method was used to encapsulate tetrachloro-tetramethyl porphyrin in NaCoX molecular sieve supercages. Characterization of the encapsulated porphyrin was carried out by UV-vis and IR Spectroscopy, DTA, SEM and EPR. A comparison was made of the activities of tetrachloro-tetramethyl porphyrin, its Co(II) complex, NaCoX molecular sieve and the encapsulated porphyrin as catalysts in the oxidation reactions of styrene and p-cresol. The stability and catalytic capability of the metalloporphyrin were increased after combination of the porphyrin with the molecular sieve. In addition, this new type of catalyst, tetrachloro-tetramethyl porphyrin encapsulated in NaCoX molecular sieve supercages, not only possesses the advantages of both the porphyrin and the molecular sieve, but also makes up for their respective deficiencies. In this study, another method called sealing–melting was also used to encapsulate the Zn(II) complex of meso-tetraphenyl-tetrabenzoporphyrin into NaY molecular sieve supercages. The catalytic capabilities of the free Zn(II) complex of meso-tetraphenyl-tetrabenzoporphyrin, the Zn(II) complex encapsulated in NaY molecular sieve supercages and the NaY molecular sieve itself in the oxidation of styrene by hydrogen peroxide were also studied. The experimental results again confirmed that both the stability and catalytic capability of the metalloporphyrin encapsulated in molecular sieve supercages are increased. © 1998 John Wiley & Sons, Ltd.