Synthesis and characterization of zeolite-encapsulated metalloporphyrins

Nakagaki, Shirley; Xavier, Claudia Regina; Wosniak, A.J.; Mangrich, A. S.; Wypych, Fernando; Cantão, Maurício Pereira; Denicoló, I; Kubota, Lauro T.

doi:10.1016/s0927-7757(99)00503-8

Cited by 72 publications

(40 citation statements)

References 39 publications

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“…8,24 Therefore, higher yields in oxidation reactions are expected for this iron porphyrin in comparison with Fe(TDFSPP). In contrast, after immobilization, the better catalytic results observed for Fe(TDFSPP) could be due to an easy access of PhIO and substrate to the iron site, based on the small size of the two ortho-fluorine substituents in comparison with orthochlorine substituents from Fe(TCFSPP).…”

Section: Resultsmentioning

confidence: 99%

“…[1][2][3][4] This class of compounds is used in solution or following immobilization in organic amorphous polymers and crystalline inorganic materials such as silica, [5][6][7] zeolites, 8,9 clay from the smectite group (montmorillonite) 10,11 and others. [12][13][14][15][16] The use of metalloporphyrins substituted with electron-withdrawing groups (the so-called second generation porphyrins 17 ) and their immobilization, has resulted in efficient and selective catalysts for oxidation reactions, since the support can impose shape selectivity and promote a special environment, favoring the approach of the substrate to the active catalytic specie.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Nakagaki¹,

Castro²,

Machado³

et al. 2006

J. Braz. Chem. Soc.

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Crisotila natural e quimicamente modificada foi usada como matrizes para imobilização de ferroporfirinas de segunda geração. As atividades catalíticas dos sólidos obtidos foram avaliadas em reações de oxidação de cicloexano, usando iodosilbenzeno como oxidante. Os resultados de catálise foram analisados e comparados aos obtidos pela imobilização das mesmas ferroporfirinas em sílica funcionalizada com 3-APTS, derivadas do tratamento ácido da crisotila. Os resultados preliminares mostraram que os catalisadores são eficientes e seletivos para a obtenção de álcool.Natural and grafted chrysotile were used as matrices for the immobilization of second generation iron porphyrins. The catalysts obtained were evaluated in the oxidation reaction of cyclohexane, using iodosylbenzene as oxidant agent. The catalyst activity for different conditions was compared with results for the same porphyrins immobilized with 3-APTS grafted disordered silica, obtained from acid-leached chrysotile. Preliminary results have shown that high activity can be obtained with short reaction times, and that the reaction is specific for alcohol.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Nakagaki¹,

Castro²,

Machado³

et al. 2006

J. Braz. Chem. Soc.

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“…[1][2][3][4][5][6][7] Porphyrin ligands with electron-withdrawing substitutes (PPEW) are currently of interest as precursors to stable metalloporphyrin catalysts for a variety of hydrocarbon-oxygenation reactions that are important for future energy development. [8][9][10][11][12][13][14][15][16][17][18][19] The effect of electronwithdrawing groups on the electron states of porphyrin macrocycles, especially of four nitrogen atoms in the porphine ring, is an important issue for studies in not only analytical chemistry, but also in coordination chemistry because it is related to the protonation of nitrogen atoms in the porphine ring and to the stability of metalloporphyrin complexes.…”

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confidence: 99%

Local Structure of Nitrogen Atoms in a Porphine Ring of meso-Phenyl Substituted Porphyrin with an Electron-Withdrawing Group Using X-ray Photoelectron Spectroscopy and X-ray Absorption Spectroscopy

et al. 2005

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Metalloporphyrins with electron-withdrawing substitutes, such as carboxyl groups, at the meso-positions, and those immobilized on inorganic supports act as efficient and selective catalysts for the oxidation of hydrocarbons. [1][2][3][4][5][6][7] Porphyrin ligands with electron-withdrawing substitutes (PPEW) are currently of interest as precursors to stable metalloporphyrin catalysts for a variety of hydrocarbon-oxygenation reactions that are important for future energy development. [8][9][10][11][12][13][14][15][16][17][18][19] The effect of electronwithdrawing groups on the electron states of porphyrin macrocycles, especially of four nitrogen atoms in the porphine ring, is an important issue for studies in not only analytical chemistry, but also in coordination chemistry because it is related to the protonation of nitrogen atoms in the porphine ring and to the stability of metalloporphyrin complexes.Changes of the local structure and electronic states between four nitrogen atoms and protons in the porphine ring in the PPEW ligand have been elucidated using ab initio calculations 20 and ionization potentials. The results of local-density functional calculations and spectroscopic studies show that they are different from the meso and β positions of a variety of multiple substituents (alkyl-, aryl-, fluoro-, chloro-, bromo-, trifluoromethyl cyano-, nitro-, etc.) in the PPEW that were provided. 21 However, information regarding molecular orbitals (MOs), including the atomic orbitals of nitrogen in these literatures was not investigated. On the other hand, because the effect of electron-withdrawing groups strongly affects the energy level of the 1s orbital for nitrogen, it is necessary to reveal the electronic effect. Therefore, X-ray photoelectron spectroscopy (XPS) is a very suitable method because it is possible to observe the atomic orbital with a characteristic energy. In addition, the X-ray absorption near-edge structure (XANES) provides an effective verification of the local structure of an absorbing atom. So far, a correlation between the energy of the 1s orbital for N in a porphine ring and the electron-withdrawing strength of meso-substituents in the PPEW has been reported to be a result of XPS and ab initio calculations. 22 On the other hand, N K XANES measurements of porphyrins have been reported for the orientation and electronic structure of macromolecular arrays containing porphyrins, 23 porphyrin thin film, 24 porphyrins in petroleum asphaltenes, 25 and porphyrins with adsorbed nitrogen monoxide. 26 Nevertheless, few studies have used a combination of XPS and XANES, a correlation between the protonation to nitrogen atoms in a porphine ring, and the strength of electronwithdrawing groups in a meso-substituted porphyrin. To show correlations in this study, the spectra of N 1s XPS and N K XANES for tetrakis(p-carboxyphenyl)porphyrin (TCPP) were measured and analyzed from an electronic state calculation using the discrete variational (DV)-Xα MO method, 27 which is a first-principle calculation that is u...

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“…The morphology and textural properties of the support can direct the substrates to the catalytically active center in a different way. 18,36,50,[76][77][78] Besides that, FeP immobilization protects the catalyst from the oxidative attack of another catalytically activated FeP, which avoids destruction of the catalytic species. In the specific case of FeP-LDHME, the microporous structure of the support may have conferred better protection to the FeP, whereas the immobilized FeP remained on the surface of the layered crystals in FeP-LDH-NO 3 , as indicated by XRD analysis (Figure 2c).…”

Section: Catalytic Oxidation Reactionsmentioning

confidence: 99%

Anionic Iron(III) Porphyrin Immobilized on/into Exfoliated Macroporous Layered Double Hydroxides as Catalyst for Oxidation Reactions

Nakagaki¹,

Castro²,

Ucoski³

et al. 2014

Journal of the Brazilian Chemical Society

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A oxidação de substratos orgânicos é uma importante classe de reações explorada visando a produção de insumos industriais tais como epóxidos, álcoois e cetonas. As metaloporfirinas são compostos com reconhecida atividade catalítica que mimetizam processos de oxidação que ocorrem em seres vivos. A sua imobilização em diferentes sólidos robustos e inertes permite a recuperação e reuso do catalisador em processos catalíticos heterogêneos. Hidróxidos duplos lamelares (LDHs) são materiais inorgânicos constituídos de hidróxidos de metais di e trivalentes, resultando em lamelas bidimensionais carregadas positivamente. Neste trabalho reportamos a preparação de catalisadores baseados na imobilização de ferroporfirina (FeP) em LDH macroporoso (LDHM) obtido pelo método de co-precipitação usando poliestireno como template, reconstrução de óxidos e esfoliação (LDHME). A imobilização da FeP no LDH intercalado com ânions nitrato obtido pelo método de co-precipitação também é reportada. Os sólidos obtidos foram caracterizados e investigados como catalisadores na oxidação do cicloocteno e cicloexano.The oxidation of organic substrates via catalytic routes is an important class of reactions to produce industrial input materials such as epoxides, alcohols, and ketones. Metalloporphyrins display recognized catalytic activity that mimics oxidation processes in living organisms. Their immobilization in different inert supports allows their recovery and reuse in heterogeneous catalytic processes. Layered double hydroxides (LDHs) are inorganic materials consisting of di-and trivalent metal hydroxides that afford bidimensional positively charged layers. This work reports on the preparation of the solid based on macroporous LDHs (LDHMs) by the co-precipitation method, which involved the use of polystyrene as template, oxides reconstruction, and exfoliation, to furnish LDHME. We also describe the immobilization of an iron(III) porphyrin (FeP) in LDHME and in LDH intercalated with nitrate anions, obtained by the co-precipitation method. Application of the immobilized catalysts in (Z)-cyclooctene and cyclohexane oxidation will help to assess their catalytic activity. Keywords: porphyrin, macroporous LDH, oxidation, biomimetic reaction, heterogeneous catalysis IntroductionThe family of enzymes collectively known as cytochrome P450 monooxygenases bear a heme prosthetic group and participate in different catalytic processes, mainly oxidative metabolism of endogenous/exogenous products in mammals. [1][2][3][4][5] Over the last years, researchers have made great efforts to develop routes that can generate robust synthetic metalloporphyrins (MPs), 6-10 aiming to mimic biological enzymes such as cytochrome P450 (biomimetic approach). Indeed, MPs can efficiently and selectively catalyze hydrocarbon oxidation.11 Some of these MPs are based on the structure of meso-tetraphenylporphyrin [H 2 (TPP)].The high efficiency and selectivity of MPs have motivated the proposition of technological catalytic systems based on this versatile family of oxidation ca...

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Synthesis and characterization of zeolite-encapsulated metalloporphyrins

Cited by 72 publications

References 39 publications

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Local Structure of Nitrogen Atoms in a Porphine Ring of meso-Phenyl Substituted Porphyrin with an Electron-Withdrawing Group Using X-ray Photoelectron Spectroscopy and X-ray Absorption Spectroscopy

Anionic Iron(III) Porphyrin Immobilized on/into Exfoliated Macroporous Layered Double Hydroxides as Catalyst for Oxidation Reactions

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