Immobilization of iron porphyrins into porous vycor glass: characterization and study of catalytic activity

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

“…A similar behavior was observed previously, 19 when metalloporphyrins were immobilized in different inorganic supports. 10,[12][13][14]36 This behavior was attributed to steric constraints caused by the support, which modified the iron porphyrin structure substantially in these supported catalysts. 33 Figure 4a and Figure 4b show the spectra of raw chrysotile and chrysotile-APTS, where no peaks are present.…”

“…The measurements suggest that no demetallation (characterized by a blue-shift of the Soret band that is associated with a significant amount of free base porphyrin [12][13][14] Figure 4f) were red-shifted when compared to those of iron porphyrins in solution (methanol:water), 388 nm for Fe(TCFSPP) and 392 nm for Fe(TDFSPP). A similar behavior was observed previously, 19 when metalloporphyrins were immobilized in different inorganic supports.…”

“…[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. [5][6][7]12,13,18 In addition, the immobilization may prevent molecular aggregation or bimolecular self-destruction reactions, which can lead to deactivation of catalytically active metalloporphyrin species.…”

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

“…[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.…”

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

“…8,15,18 To minimize such problems, researchers have turned to the synthesis of new robust and resistant porphyrin structures 10,22 as well as to immobilization of these catalysts in different inorganic supports. [22][23][24][25][26][27][28][29][30][31][32][33] Catalyst immobilization can facilitate catalyst recovery from the reaction medium, to enable their reuse and recycling. 17,[33][34][35][36][37][38][39] This is particularly attractive from an economical and environmental viewpoint.…”