Synthesis, characterization, and catalytic activity of anionic iron(III) porphyrins intercalated into layered double hydroxides

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

“…13 The first MP-based catalytic system relied on the Fe(III) complex [Fe(TPP)Cl] as catalyst and iodosylbenzene (PhIO) as oxidant; 14 it mimicked cytochrome P450 in many reactions. Since then, the use of MPs, specially FePs and MnPs, in oxidative systems [6][7][8][9][10][11][14][15][16][17][18][19][20][21] has attracted considerable attention, because these complexes can effectively and selectively catalyze a series of oxidation reactions in homogeneous medium, among which epoxidation and hydroxylation stand out. [15][16][17][18][19][20][21] Despite their efficiency in homogeneous systems, the use of this family of complexes in solution has raised concerns.…”

“…10 Another difficulty posed by homogeneous catalysts is their recovery, reuse, and recycling, which could prevent the design of a technological process. 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.…”

“…In this context, layered double hydroxides (LDHs) have emerged as interesting supports to immobilize a variety of MPs. 18,23,[40][41][42][43][44] LDHs are synthetic layered compounds that contain divalent and trivalent metal cations [M(II) and M(III)] in a structure derived from the mineral brucite. In LDHs, M(III) metal ions replace part of the M(II) metals in the brucitelike structure, to give excess positive charge in the layers, counterbalanced by intercalating hydrated anions.…”

“…Some kind of interaction involving the modifier on the support and/or on the MP might occur, which shall not only increase the rate of MP immobilization, 40 but also provide a new solid catalyst with unprecedented efficiency and selectivity. 8,18,50 There has been a recent surge in scientist's interest in nanostructured LDHs. This type of solid can be achieved by controlling the textural properties of the material in terms of morphology, particle size, specific area, and porosity.…”

“…41,[51][52][53] Our group has already intercalated different anionic FePs in macroporous LDHs, to obtain more efficient and selective catalysts for heterogeneous hydroxylation and epoxidation reactions than their homogeneous counterparts. 18 Coprecipitation using a template like polystyrene spheres furnishes an LDH structure bearing macropores, which is suitable for immobilization of countless FePs. 41 In this work, we have prepared two solids by immobilizing the [Fe(TDCSPP)Cl] (Figure 1) …”