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Pure Appl. Chem., 2009, Vol. 81, No. 11, pp. 2025-2033

Published online 2009-10-29

Immobilization of 5,10,15,20-tetrakis-(2-fluorophenyl)porphyrin into MCM-41 and NaY: Routes toward photodegradation of pesticides

Monica Silva1, Maria E. Azenha1*, Mariette M. Pereira1, Hugh D. Burrows1, Mohamed Sarakha2, Maria F. Ribeiro3, Auguste Fernandes3, Paula Monsanto4 and Fernando Castanheira4

1 Department of Chemistry, Faculty of Sciences and Technology, Coimbra University, Rua Larga, 3004-535 Coimbra, Portugal
2 Laboratoire de Photochimie Moléculaire et Macromoléculaire, Université Blaise Pascal, 24, Avenue des Landais, 63177 Aubière, France
3 IBB, Department of Chemical Engineering, IST, Lisbon Technical University, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
4 National Institute of Legal Medicine, Centre Branch, Department of Forensic Toxicology, Largo da Sé Nova, 3000-213 Coimbra, Portugal

Abstract: NaY zeolite and MCM-41 mesoporous molecular sieve were used as supports for immobilization of 5,10,15,20-tetrakis-(2-fluorophenyl)porphyrin (TFPP) using adsorption and ship-in-the-bottle routes involving the nitrobenzene method. The materials obtained were characterized by thermogravimetry/differential thermal analysis (TG/DTA), nitrogen adsorption, UV–vis absorption, diffuse reflectance (DRS), and luminescence spectroscopy. Although the porphyrin could easily be synthesized inside MCM-41 pores using the ship-in-the-bottle route, no significant porphyrin was formed in the smaller supercages of NaY zeolite, since the reaction stops at the dipyrrolylmethene intermediate (FDPM). Promising preliminary studies were made in the photodegradation of the pesticides, 2,3,5-trimethylphenol (TMP) and mecoprop (MCPP), using as catalyst TFPP encapsulated in mesoporous MCM‑41 material. The 2-hydroxy-methyl-hydroquinone and 4-chloro-2-methylphenol were identified as the main degradation products of MCPP. The encapsulated system resulting from the TFPP template synthesis shows significantly enhanced performance when compared with adsorbed porphyrin in both supports.