Journal of Molecular Catalysis A: Chemical 174 (2001) 279–288 Cationic manganese(III) porphyrins bound to a novel bis-functionalised silica as catalysts for hydrocarbons oxygenation by iodosylbenzene and hydrogen peroxide Fábio S. Vinhado, Cynthia M.C. Prado-Manso, Hérica C. Sacco, Yassuko Iamamoto ∗ Departamento de Qu´ ımica, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, CEP 14040-901, Ribeirão Preto, SP, Brazil Received 22 January 2001; accepted 24 April 2001 Abstract The cationic manganese porphyrins: manganese(III) 5,10,15-tris(2,6-dichlorophenyl)-20-(4-N-methylpyridyl)porphyrin ([Mn{M(4-N-MePy)TDCPP}] 2+ ), 5,10,15,20-tetra(2,3,5,6-tetrafluoro-4-trimethylammoniumphenyl)porphyrin ([Mn(TF4T- MAPP)] 5+ ) and 5,10,15,20-tetra(4-N-methylpyridyl)porphyrin ([Mn{T(4-N-MePy)P}] 5+ ) supported on silica modified with propylimidazole (IPG), sulfonatophenyl (SiSO 3 - ) and both propylimidazole and sulfonatophenyl (SiSO 3 - (IPG)) have been studied as catalysts in the epoxidation of (Z)-cyclooctene and oxidation of cyclohexane. High yields of products were ob- tained using PhIO as oxidant without leaching, except for the IPG, of the catalyst from the surface of the support. The catalysts also have been used with H 2 O 2 in the epoxidation of (Z)-cyclooctene with and without a co-catalyst (imidazole or ammonium acetate). The best catalyst [Mn{T(F4TMAPP)}]-SiSO 3 (IPG) achieved almost 200 turnovers of the product cis-epoxycyclooctane using ammonium acetate as co-catalyst. The analogous homogeneous systems have been studied for comparison, but they did not reach the same efficiency. With these studies the two-fold role of imidazole in oxygenations of hydrocarbons by H 2 O 2 and Mn(III) porphyrins was confirmed. The characterisation of supported metalloporphyrins by UV–VIS spectroscopy is reported too. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Manganese(III) porphyrin; Hydrocarbons oxygenation; Role of co-catalyst; Bis-functional support; Hydrogen peroxide 1. Introduction In the search of versatile catalytic systems that mimic the action of cytochrome P-450-dependent monooxygenases, some synthetic metalloporphyrins have been found to be highly efficient homogeneous catalysts for alkene epoxidation and alkane hydrox- ylation, using oxygen atom donors such as iodosyl- benzene (PhIO), HSO 5 - or H 2 O 2 . However, these homogeneous catalysts have some drawbacks: (i) they ∗ Corresponding author. Tel.: +55-16-602-3782; fax: +55-16-633-8151. E-mail address: iamamoto@usp.br (Y. Iamamoto). can be easily destroyed during the reaction and (ii) it is not easy to recover the catalyst at the end of the reaction for re-use [1–3]. In recent publications it has been argued that these limitations might be avoided by binding the metallo- porphyrins to solid materials [4]. The support can also provide steric and electronic effects, which, in some respects, are analogous to the influence of the protein matrix of hemoproteins [5,6]. There are reports using metalloporphyrins, bound to silica [7], ion exchange resins [8] and clays [9] as catalysts in reactions of hydrocarbons oxygenation by PhIO with some sys- tems reaching high yields of products and improved regioselectivity [9]. Within this context it would be 1381-1169/01/$ – see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S1381-1169(01)00200-X