Manganese porphyrin functionalized on Fe3O4@nSiO(2)@MCM-41 magnetic composite: Structural characterization and catalytic activity as cytochrome P450 model

Author(s)

Zanardi, Fabricio B. ^[1] ; Barbosa, Isaltino A. ^[1] ; de Sousa Filho, Paulo C. ^[1] ; Zanatta, Lucas D. ^[1] ; da Silva, Douglas L. ^[1] ; Serra, Osvaldo A. ^[1] ; Iamamoto, Yassuko ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Chem, Bioinorgan Chem Lab, BR-14040901 Ribeirao Preto - Brazil

• Document type: Journal article
• Source: Microporous and Mesoporous Materials; v. 219, p. 161-171, JAN 1 2016.
• Web of Science Citations: 27

Abstract

This study reports on the preparation of heterogeneous catalysts with two different pore sizes, the Fe3O4@nSiO(2)@MCM-41-MnP and Fe3O4@nSiO(2)@MCM-41(E)-MnP catalysts. Such systems ally the catalytic properties of metalloporphyrins (MeP) with the magnetic properties of magnetite nanoparticles (Fe3O4) in a mesoporous MCM-41 silica matrix. The synthesis of Fe3O4 nanoparticles was followed by the surface coating with a thin silica layer (Fe3O4@nSiO(2)). Then, an MCM-41-type ordered mesoporous silica structure was grown over the initial particles in the presence of CTAB as surfactant and TEOS as the silica precursor, to yield the Fe3O4@nSiO(2)@MCM-41 solid. In this step, mesitylene can also be incorporated as a structure expanding agent for the production of larger pores, thus yielding the Fe3O4@nSiO(2) MCM-41(E) solids. The resulting composites were further functionalized with aminopropyl groups by the silylating agent APTES. This enabled the covalent immobilization of manganese(III)-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (Mn(TPF5PP)) onto the composites via a aromatic nucleophilic substitution reaction, to afford the Fe3O4@nSiO(2)@MCM-41-MnP and Fe3O4@nSiO(2)@MCM-41(E)-MnP catalysts. Characterization of the catalysts by XRD, UV Vis, DR UV vis, FTIR, SEM, TEM, VSM and N-2 adsorption/desorption isotherms, aided understanding the catalyst structure and morphology. The catalytic activity of the catalysts in hydrocarbon oxidation ((Z)-cyclooctene and cyclohexane) was evaluated; iodosylbenzene (PhIO) was used as the oxygen donor agent. The catalytic tests demonstrated higher yields of epoxide for Fe3O4@nSiO(2)@MCM-41(E)-MnP than Fe3O4@nSiO(2)@MCM-41-MnP catalyst, which can be attributed to the larger pore sizes. Both catalysts were selective for the cyclohexanol product, thus indicating a P450-type biomimetic behavior. (C) 2015 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 13/01669-1 - Nanostructured phosphors and core@shell systems containing rare earths: applications in biological labeling, lighting, and visualization
• Grantee: Paulo Cesar de Sousa Filho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/08439-1 - Manganeseporphyrin immobilized onto Fe3O4@nSiO2@MCM-41 magnetic composite: biomimetic catalyst applied on hydrocarbons and drug oxidation.
• Grantee: Fabrício Bortulucci Zanardi
• Support Opportunities: Scholarships in Brazil - Master