Preparation and catalysis of DMY and MCM-41 encapsulated cationic Mn(III)–porphyrin complex

Role of decomposition products in the oxidation of cyclohexene using a manganese(III) complex

Metal complexes are extensively explored as catalysts for oxidation reactions; molecular-based mechanisms are usually proposed for such reactions. However, the roles of the decomposition products of these materials in the catalytic process have yet to be considered for these reactions. Herein, the cyclohexene oxidation in the presence of manganese(III) 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine chloride tetrakis(methochloride) (1) in a heterogeneous system via loading the complex on an SBA-15 substrate is performed as a study case. A molecular-based mechanism is usually suggested for such a metal complex. Herein, 1 was selected and investigated under the oxidation reaction by iodosylbenzene or (diacetoxyiodo)benzene (PhI(OAc)₂). In addition to 1, at least one of the decomposition products of 1 formed during the oxidation reaction could be considered a candidate to catalyze the reaction. First-principles calculations show that Mn dissolution is energetically feasible in the presence of iodosylbenzene and trace amounts of water.

Porphyrins and Phthalocyanines on Solid-State Mesoporous Matrices as Catalysts in Oxidation Reactions

The review presents recent examples of heterogenic catalysts based on porphyrins and phthalocyanines loaded on mesoporous materials, such as MCM-41, SBA-15, MCM-48, SBA-16 or Al-MCM-41. Heterogenic approach to catalysis eases recovery, reuse and prevent macrocycle aggregation. In this application, mesoporous silica is a promising candidate for anchoring macrocycle and obtaining a new catalyst. Introduction of porphyrin or phthalocyanine into the mesoporous material may be performed through adsorption of the macrocycle, or by its in situ formation—by reaction of substrates introduced to the pores of the catalytic material. Catalytic reactions studied are oxidation processes, focused on alkane, alkene or arene as substrates. The products obtained are usually epoxides, alcohols, ketones, aldehydes or acids. The greatest interest lies in oxidation of cyclohexane and cyclohexene, as a source of adypic acid and derivatives. Some of the reactions may be viewed as biomimetic processes, resembling processes that occur in vivo and are catalyzed by cytochrome P450 enzyme family.

Second-Generation Manganese(III) Porphyrins Bearing 3,5-Dichloropyridyl Units: Innovative Homogeneous and Heterogeneous Catalysts for the Epoxidation of Alkenes

The synthesis, characterisation and homogeneous catalytic oxidation results of two manganese(III) porphyrins of the so-called second-generation of metalloporphyrin catalysts, containing one or four 3,5-dichloropyridyl substituents at the meso positions are reported for the first time. The catalytic efficiency of these novel manganese(III) porphyrins was evaluated in the oxidation of cyclooctene and styrene using aqueous hydrogen peroxide as the oxidant, under homogeneous conditions. High conversions were obtained in the presence of both catalysts, obtaining the corresponding epoxide as the major product. The asymmetric metalloporphyrin, chloro[5,10,15-tris(2,6-dichlorophenyl)-20-(3,5-dichloropyridin-4-yl)porphyrinate]manganese(III), CAT-4, evidences a similar activity to that obtained with the well-known and highly efficient second-generation metalloporphyrin catalyst, chloro[5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrinate]manganese(III), CAT-2. CAT-4 was covalently attached onto Merrifield resin and 3-bromopropylsilica supports. The solid materials obtained were characterized by several techniques including diffuse reflectance, UV—VIS spectrophotometry, SEM and XPS. The catalytic results for the oxidation of cyclooctene and styrene using the immobilized catalysts are also presented. The Merrifield-supported catalyst showed to be very efficient, leading to five catalytic cycles in the oxidation of cyclooctene, using tert-butyl hydroperoxide as the oxidant.

Heterogeneous catalysis with encapsulated haem and other synthetic porphyrins: Harnessing the power of porphyrins for oxidation reactions

Encapsulated metalloporphyrins have been widely studied for their use as efficient heterogeneous catalysts, inspired by the known catalytic activity of porphyrins in haemoproteins. The oxidation of organic substrates by haemoproteins is one of the well-known roles of these proteins, in which the haem (ferriprotoporphyrin IX = FePPIX) cofactor is the centre of reactivity. While these porphyrins are highly efficient catalysts in the protein environment, once removed, they quickly lose their reactivity. It is for this reason that they have garnered much interest in the field of heterogeneous catalysis of oxidation reactions. This review details current research in the field, focusing on the application of encapsulated haem, and other synthetic metalloporphyrins, applied to oxidation reactions.

Practicably efficient ethylbenzene oxidation catalyzed by manganese tetrakis(4-sulfonatophenyl)porphyrin grafted to powdered chitosan

Manganese tetrakis(4-sulfonatophenyl)porphyrin chloride was grafted onto powdered chitosan via an acid–base reaction and ligation. The grafted catalyst was characterized by transmission electron microscopy, ultraviolet and visible spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry and thermogravimetry. Ethylbenzene oxidation with O[Formula: see text] by the catalyst in the absence of additives and solvents can achieve moderate yields (approximately 30%) of acetophenone and phenethyl alcohol. The grafted catalyst can be reused four times for oxidation reactions. The results indicate that the catalytic activity of manganese tetrakis(4-sulfonatophenyl)porphyrin chloride is promoted by the ligation and grafting function of the amino groups in the powdered chitosan.

Chiral MnIII (Salen) Covalently Bonded on Modified ZPS-PVPA and ZPS-IPPA as Efficient Catalysts for Enantioselective Epoxidation of Unfunctionalized Olefins

Chiral MnIII (salen) complex supported on modified ZPS-PVPA (zirconium poly(styrene-phenylvinylphosphonate)) and ZPS-IPPA (zirconium poly(styrene-isopropenyl phosphonate)) were prepared using ⁻CH₂Cl as a reactive surface modifier by a covalent grafting method. The supported catalysts showed higher chiral induction (ee: 72%⁻83%) compared with the corresponding homogeneous catalyst (ee: 54%) for asymmetric epoxidation of α-methylstrene in the presence of 4-phenylpyridine N-oxide (PPNO) as axial base using NaClO as an oxidant. ZPS-PVPA-based catalyst 1, with a larger pore diameter and surface area, was found to be more active than ZPS-IPPA-based catalyst 2. In addition, bulkier alkene-like indene, was efficiently epoxidized with these supported catalysts (ee: 96%⁻99%), the results were much higher than those for the homogeneous system (ee: 65%). Moreover, the prepared catalysts were relatively stable and can be recycled at least eight times without significant loss of activity and enantioselectivity.

Porphyrin-Based Porous Organic Frameworks as a Biomimetic Catalyst for Highly Efficient Colorimetric Immunoassay

Herein, we synthesized a cost-effective iron porphyrin (FePor)-based covalent organic polymer (COP), FePor-TFPA-COP, through an easy aromatic substitution reaction between pyrrole and tris(4-formylphenyl)amine (TFPA). The triangular pyramid-shaped, N-centric structure of TFPA facilitated the formation of FePor-TFPA-COP with three-dimensional porous structure, larger surface area, and abundant surface catalytically active sites. FePor-TFPA-COP exhibited strong intrinsic peroxidase activity toward a classical peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), in the presence of H₂O₂. Compared with horseradish peroxidase (HRP), FePor-TFPA-COP exhibited several advantages such as easy storage, high sensitivity, and prominently chemical and catalytic stability under the harsh conditions, which guaranteed the accuracy and reliability of measurements. Utilizing the excellent catalytic activity, a FePor-TFPA-COP-based colorimetric immunoassay was first established for α-fetoprotein (AFP) detection and showed high sensitivity, stability, and acceptable reproducibility. The linear response range for AFP was 5 pg/mL to 100 ng/mL and the detection limitation was 1 pg/mL. The routine provided a brilliant biomimetic catalyst to develop the nonenzyme immunoassay. More importantly, the high chemical and catalytic stability and sensitivity facilitated future practical applications under various conditions.

Oxygen oxidation of ethylbenzene over manganese porphyrin is promoted by the axial nitrogen coordination in powdered chitosan

A less wasteful production method of oxidation ethylbenzene to acetophenone and phenethyl alcohol was adviced. It revealed an important role in tuning catalytic reactivity of metalloporphyrins by the axial ligand for oxidation of hydrocarbon.

Facile one-pot synthesis of porphyrin based porous polymer networks (PPNs) as biomimetic catalysts

Two stable porphyrin based porous polymer networks (PPNs) were synthesized, and their biomimetic catalytic activities were studied.

Porphyrin functionalized porous carbon derived from metal–organic framework as a biomimetic catalyst for electrochemical biosensing

A novel biomimetic catalyst was designed by the assembly of porphyrin on porous carbon derived from metal–organic frameworks for electrochemical biosensing.

Anchorage of a ruthenium complex into modified MOF: synergistic effects for selective oxidation of aromatic and heteroaromatic compounds

The structure of IRMOF-3 was modified with pyridine-2-aldehyde and then the Schiff base moieties were used to anchor ruthenium complex to this metal–organic framework.

Manganese meso-tetra-4-carboxyphenylporphyrin immobilized on MCM-41 as catalyst for oxidation of olefins with different oxygen donors in stoichiometric conditions

Oxidation of olefins with tert-butyl hydroperoxide (TBHP), tetra-n-butylammonium periodate (TBAP) and potassium peroxomonosulfate (Oxone) in the presence of MCM-41 immobilized meso-tetra-4-carboxyphenylporphyrinatomanganese(III) acetate has been studied. The results of this study show better catalytic performance of the heterogonous catalyst using TBHP as oxidant in comparison with Oxone and TBAP in oxidation of the used olefins with the exception of cyclooctene. However, different order of reactivity of various olefins has been observed in the presence of Oxone and TBHP. In spite of the absence of good electron-withdrawing groups at the periphery of porphyrin ligand, the catalyst was recovered and reused (at least four times) without detectable catalyst leaching or a significant loss of the catalytic efficiency. All results have been obtained in the absence of using excess molar ratios of olefin to the oxidant, commonly employed as a strategy to overcome the instability of metalloporphyrins in oxidative conditions.

Manganese(III) Porphyrin Covalently Bound to sol-gel Derived Silica (Mn(III) Porphyrinosilica): A Reusable and Green Heterogeneous Photocatalyst for Oxidative Decarboxylation of α-Arylacetic Acids with H2O2

Manganese(III) (5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin)chloride, MnIII(TDCPP)Cl, was chemically (covalently) bound to a silica matrix by a sol-gel method and used as a new reusable heterogeneous photocatalyt for the selective and efficient oxidative decarboxylation of α-arylacetic acids with H2O2 as a mild and clean oxidant at room temperature. The activity of this heterogeneous photocatalytic system is higher than that of a corresponding homogeneous systems and the catalyst can be reused several times without loss of its activity and selectivity.

Polystyrene-bound Mn(T4PyP): a highly efficient and reusable catalyst for biomimetic oxidative decarboxylation of carboxylic acids with sodium periodate

In this report, highly efficient oxidative decarboxylation of carboxylic acids with sodium periodate catalyzed by a supported manganese(III) porphyrin is described. In the presence of manganese(III) tetra(4-pyridyl)porphyrin supported on cross-linked chloromethylated polystyrene, [Mn(T4PyP)-CMP], as catalyst, carboxylic acids were converted to their corresponding carbonyl compounds via oxidative decarboxylation with sodium periodate using imidazole as axial ligand. The oxidation of anti-inflammatory drugs such Indomethacin and Ibuprofen was carried out successfully and the decarboxylated products were obtained. This catalyst can be reused several times without loss of its catalytic activity in the oxidation reactions.

Supported metalloporphyrin catalysts for alkene epoxidation

This review is devoted to the recent advances in the preparation of immobilised metalloporphyrins and their use as heterogeneous catalysts for alkene epoxidation. The wide range of supports, nature of attachments, and metalloporphyrins that have been reported is detailed and a comparison is made between the activities of the resulting catalysts in the epoxidation of different alkenes. The important issue of recyclability of the metalloporphyrins is also covered.