Metalloporphyrins: Bioinspired Oxidation Catalysts - American

Review Cite This: ACS Catal. 2018, 8, 10784−10808

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Metalloporphyrins: Bioinspired Oxidation Catalysts Mariette M. Pereira,* Lucas D. Dias, and Mário J. F. Calvete*

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CQC, Coimbra Chemistry Centre, Department of Chemistry, Faculty of Science and Technology, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal ABSTRACT: The utilization of metalloporphyrins as bioinspired oxidation catalysts is an evolving topic of research. By understanding the cytochrome P-450 mechanism of action, chemists have been able to successfully mimic several types of oxidation reactions using metalloporphyrins as catalysts. At first, homogeneous systems presented the most amenable strategy for oxidizing a vast array of substrates; however, current environmental concerns have directed research in this field to the design, synthesis, and application of heterogeneous catalysts, as well as avoiding the use of highly pollutant cooxidants and/or co-catalysts. Herein, we review the past decade (from 2008) concerning the use of solely molecular oxygen as an environmentally benign oxidant source, in oxidation reactions catalyzed by bioinspired metalloporphyrin analogues. We did not intend to create a comprehensive review; instead we highlight the most important and illustrative examples for this period. We emphasize the application of such catalysts on the oxidation reactions of many relevant substrates using homogeneous and heterogeneous metalloporphyrin-based catalysts, mostly using inorganic supports for more accessible re-utilization protocols. KEYWORDS: biomimetic catalytic oxidation, molecular oxygen, metalloporphyrins, homogeneous reactions, heterogeneous reactions

1. INTRODUCTION The transposition of mechanisms of action from natural systems to laboratory and/or industrial levels is an area of great interest which has brought together many multi-disciplinary research teams, from fields including chemistry, materials, and biology. From the multiple existing processes, we highlight the biomimetic systems from the enzyme family of cytochrome P450. This enzyme was discovered in 1958 by Garfinkel1 and Klingenberg2 (identified in 1962 by Sato3), and since then, numerous advances have been made in the understanding of cytochrome P-450’s in vivo action as well as its function as a catalyst in the degradation of xenobiotic compounds,4−32 with many landmarks being achieved, as pictured in Figure 1. These advances have also largely contributed to the development of parallel avenues in the chemistry domain, namely in the pursuit of improved methods for the synthesis of meso-tetrasubstituted porphyrins and its application as biomimetic systems in oxidation reactions. Regarding the synthesis of meso-substituted porphyrins, one must note the pioneering one-pot work of Rothemund,33,34 followed by Adler and Longo’s seminal work,35−37 complemented by Gonsalves and Pereira’s nitrobenzene method along with their first twostep approach.38−40 Regarding the last methodology, Lindsey’s trajectory is considered a landmark in the synthesis of mesosubstituted porphyrins,41−45 allowing the preparation of substantial amounts of meso-tetraarylporphyrins45−58 bearing bulky groups in the porphyrin’s ortho-phenyl positions,39,43,44 particularly halogens, which most probably represents one of the biggest breakthroughs for the application of meso© XXXX American Chemical Society

arylporphyrins in oxidative catalysis. Synthetic advances were continued, and more recently, Pereira’s group and several others developed synthetic methods to improve one- and twostep methodologies, using alternative catalysts,59−65 alternative environmentally benign synthetic methods,66−71 and flow chemistry72 (Figure 2). Concerning the development of biomimetic oxidative catalytic systems, the pioneering work of Groves is acclaimed, where oxidation reactions, namely hydroxylation and epoxidation of olefins, were described using iodosylbenzene as oxidant.74−78 Since then, the number of reports has multiplied, testing the effects of metal, macrocycle structure, and particularly the oxygen donor agent.73 Of the several available oxygen donors, which include sodium hypochlorite (NaOCl), iodosylbenzene (PhIO), alkyl peroxides (ROOH), hydrogen peroxide (H2O2), and oxygen (O2), the latter is, undoubtedly, the most attractive, given its ubiquity and convenient handling, as well as its ability to mimic the cytochrome P-450 mechanism of action.79,80 The utilization of O2, whose ground state is a low-reactivity triplet, in biomimetic catalytic systems requires the presence of an electron donor to initiate the catalytic cycle. This can be the porphyrin itself, as described by Groves in his seminal work using ruthenium porphyrins,81 aldehydes in systems following Mukaiyama-type mechanisms,82 and others.83−85 It is generally accepted73 that the Received: May 15, 2018 Revised: September 20, 2018 Published: October 10, 2018 10784

DOI: 10.1021/acscatal.8b01871 ACS Catal. 2018, 8, 10784−10808

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Figure 1. Historical perspective of the determination of cytochrome P-450’s structure and its function.

Figure 2. Landmarks in meso-arylporphyrin synthesis.

Figure 3. Catalytic cycle of dioxygen activation by cytochrome P-450. Adapted with permission from ref 73. Copyright 2018 ACS.

mono-oxygenase-mediated biological oxygenation mechanism (Figure 3) involves two-electron reduction, with those electrons provided by the NADPH reductase. The first electron is used to reduce the Fe(III) ferric species to an Fe(II) ferrous species. An electron is then transferred from iron(II) to O2, forming the ferric-superoxo intermediate. Subsequently, a second electron and a proton are transferred to the ferric-superoxo intermediate to produce a ferric(hydro)peroxo intermediate, usually known as compound 0, that is able to generate the oxo-iron(IV) porphyrin cation radical intermediate, compound I. On the other hand, the

ferric-(hydro)peroxo intermediate (compound 0) may be also produced via H2O2 binding to the ferric species, also known as peroxide shunt. This intermediate is accepted to be one of the active species of biomimetic epoxidation reactions using H2O2 as oxidant.86 The formation of an oxo-iron(IV) porphyrin cation radical (compound I) is then promoted by protonation of compound 0 at the distal oxygen, followed by heterolytic scission of the O−O bond and water elimination. The oxoiron(IV) porphyrin cation radical (compound 1) then promotes the activation of C−H substrates via hydrogen atom transfer (HAT). Subsequently, the incipient substrate 10785


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ACS Catalysis radical (R•) recombines with the oxo-iron(IV) compound II via oxygen rebound to afford the desired hydroxylation products. In this Review we will not discuss the mechanistic aspects in depth, as that discussion has been recently superbly presented by both Goldberg85 and Groves.73 Performing a critical literature survey, we find that several reviews have been published; however, most past reviews consider mechanistic aspects, the whole possible range of oxidants used, and/or all structural catalyst types.84,87−102 Herein, we consider that a review on the application of biomimetic oxidation systems that use solely molecular oxygen as oxidant would be important for the current state of the art in the field. Therefore, this Review covers the past decade and is organized by oxidation reactions for each family of substrates, namely, alkyl benzenes, cycloalkanes, olefins, alcohols, and ketones. The homogeneous and heterogeneous catalysts are presented with sequential numbering, aiming to deliver a conclusion of the best catalytic system for each type of substrate used, always considering their re-utilization as a significant factor. This approach could provide a different insight on the use of metalloporphyrins as biomimetic catalysts as well as an anticipated potential transposition of these systems to the laboratory/industrial level.

only 37% and 45% were obtained. This points out that the mechanism of p-cresol oxidation under basic conditions with Co(III) porphyrins may involve an auto-oxidation process,105 yielding preferentially the p-methoxybenzaldehyde,106 while the Fe(III) and Mn(III) catalysts may preferentially involve the formation of oxo-metal(IV) porphyrin cation radical, compound 1 (Figure 3). The authors also compared the effect of the oxidation state of cobalt(II) versus cobalt(III) porphyrins on the activity and selectivity of catalytic oxidation of p-cresol, and no significant effect was observed. This may be attributed to the fact that Co(II) metalloporphyrin complexes is prone to be oxidized to Co(III) with O2,107 following then the auto-oxidation mechanism. Guo108 reported the investigation of the oxygen pressure influence in the homogeneous liquid-phase aerobic oxidation of toluene, catalyzed by μ-oxo-Fe(III) dimer 4Fe (Figure 4). Using toluene in neat conditions and the catalyst (10 × 10−6 M), the authors observed that, when the partial pressure of oxygen in the feed was ≤0.070 MPa at 190 °C, the oxidation of toluene was controlled by oxygen transfer; otherwise the reaction was controlled by kinetics (Scheme 2). This allowed them to optimize the reaction conditions to the preferential formation of benzyl alcohol (oxygen pressure control) or benzoic acid (kinetic control). Zhou and Hu109 performed the liquid-phase oxidation of pxylene using air as oxygen source, catalyzed by Fe(III), Co(II), or Mn(III) metallo-deuteroporphyins 6 (natural-based porphyrin) (Figure 4), and compared the results with those obtained using the same metal complexes of meso-tetraphenylporphyrins type 3 (Figure 4). Typically (Scheme 3), the experiments were carried out using 1 L of p-xylene, at 150 °C, with an air pressure of 0.8 MPa and a 2.5 × 10−4 mol% catalyst loading, and 6Co exhibited the highest activity in the reaction (15% conversion). The authors also found that catalysts of type 5 were, in general, two times more active than the metalloporphyrins of type 3. Regarding selectivity, it was found that the major products in the oxidation of p-xylene catalyzed by 6Fe (the best catalyst) were p-methylbenzaldehyde (60%), p-methylbenzyl alcohol (29%), and p-methylbenzoic acid (11%).109 The synthesis of porous alkynylporphyrin conjugated organic polymer 7Mn was reported by Yang,110,111 using Mn(III) 5,10,15,20-tetrakis-(4′-ethynylphenyl)porphyrin and Mn(III) 5,10,15,20-tetrakis-(4′-bromophenyl)porphyrin as building blocks, through Sonogashira coupling reaction (Scheme 4). 7Mn was applied as heterogeneous catalyst for the oxidation of toluene, using molecular oxygen as oxidant, under mild conditions (160 °C for 5 h). The conversion of toluene was ca. 10%, with selectivity for benzaldehyde (42%) and benzyl alcohol (28%). The authors also reported that 7Mn was structurally stable and recoverable through centrifugation and filtration, with similar conversions for five cycles. Efficient oxidation reactions of ethylbenzene, catalyzed by polymer-supported, porphyrin-based catalysts 8−13, were also reported by Wang (Scheme 5).112,113 In the first approach,112 three metalloporphyrins (cobalt, iron, and manganese) were immobilized on silica gel grafted copolymer poly(4-vinylpyridine-co-styrene), through axial coordination, yielding supported catalysts 8 (Fe, Co, and Mn). To further stress the influence of the axial ligands on the catalytic performance of supported metalloporphyrins, poly(glycidyl methacrylate) grafted to SiO2 was also used as support to produce catalyst 9,

2. HOMOGENEOUS VERSUS HETEROGENEOUS OXIDATION REACTIONS CATALYZED BY METALLOPORPHYRINS USING MOLECULAR OXYGEN AS OXIDANT 2.1. C−H Oxidations. 2.1.1. Alkyl Benzenes. Many compounds are prone to be oxidized by metalloporphyrins with molecular oxygen closely mimicking the cytochrome P450 mechanism, as was recently reviewed. To infer the effect of the substituents at the periphery of metalloporphyrins, Wang104 investigated the homogeneous oxidation of p-cresol catalyzed by Fe(III), Mn(III), and Co(III) complexes of metalloporphyrins 1 and 2 (Figure 4), bearing a methoxy donor group and a nitro attracting group, respectively, in 0.002 mol% loading, using NaOH−methanol solution as solvent, under an O2 positive flow of 20 mL/min at atmospheric pressure and 70 °C, for 10 h (Scheme 1). Scheme 1. Homogeneous Oxidation of p- and o-Cresol Catalyzed by Metalloporphyrins

In the oxidation reaction of p-cresol, the authors104 observed a significant effect of porphyrin structure, regardless of the metal usedCo(III), Mn(III), or Fe(III)with the metalloporphyrin bearing the methoxy electron donor group, type 1, being the catalyst with high activity. On the other hand, the selectivity for the formation of p-hydroxybenzaldehyde was quite dependent on the metal, the best selectivity of 60% being obtained with 1Co(III), while with 1Fe(III) and 1Mn(III) 10786


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Figure 4. Homogeneous and heterogeneous metalloporphyrin catalysts for C−H oxidation of alkylbenzenes. Catalyst MOF 15Cu structure was adapted with permission from ref 103. Copyright 2017 John Wiley and Sons.

with catalyst loading of 1.7 × 10−2 mol%. The authors observed that the supported catalyst 8Co was the best one, yielding acetophenone in 25% yield,112 confirming the beneficial influence of pyridine axial coordination for both immobilization and activation of the catalyst. The authors then studied the metal influence in the catalytic activity of 8Fe, 8Co,

which was linked by peripheral covalent attachment of the cobalt porphyrin to the SiO2-based support. The catalytic performances of the supported catalysts 8 and 9 for the oxidation of ethylbenzene, in the absence of any reductant and solvent, were investigated. Oxidation reactions were carried out at 120 °C under 0.1 MPa pressure for 12 h, 10787


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catalytic activity and efficiency in the oxidation of ethylbenzene, at 155 °C under 0.04 m3/h air flow (2.5 h with catalyst load = 1.14 × 10−6 mol Mn porphyrin), were increased by the presence of chitosan. While the related homogeneous manganese porphyrin catalyst gave conversion of 11% and ketone selectivity of 51%, catalyst 13Mn provided conversion of 20% and similar selectivity. However, reusability was not very successful, as the conversion by catalyst 13Mn was lowered from 20% to 14% immediately on the second run, attributed by the authors to instability of chitosan against high temperatures and oxidation conditions for long periods. To study the substituent effect on the catalysts structure, She and Fu115 evaluated several metalloporphyrins in homogeneous oxidation of substituted ethylbenzene derivatives. Using p-nitroethylbenzene as model substrate, catalysts 3 and 5Fe were tested with 1 × 10−3 mol% load, without solvent, under a O2 pressure of 0.1 MPa at 140 °C, for 12 h, mainly yielding pnitroacetophenone (Scheme 6). The authors observed that the monomers of type 3 were the most active (up 56% conversion, for 3Co), while the dimer 5Fe displayed the lowest activity (29%).

Scheme 2. Homogeneous Liquid-Phase Aerobic Oxidation of Toluene, Catalyzed by μ-Oxo Fe(III) Dimer, in the Absence of Additives and under Solventless Conditions

Scheme 3. Homogeneous Oxidation of p-Xylene with Air, Catalyzed by Metalloporphyins, in the Absence of Additives, Solventless, and Gram-Scale Conditions

Scheme 4. Oxidation of Toluene Using Molecular Oxygen Catalyzed by Conjugated Nanoporous Alkynyl Metalloporphyrin Framework

Scheme 6. Effect of Metalloporphyrin Catalysts in Neat Homogeneous Oxidation of Substituted Ethylbenzene Derivatives, Using O2 as Oxidant Scheme 5. Dioxygen-Mediated Oxidation Reactions of Ethylbenzene, Catalyzed by Organic Polymer-Supported, Porphyrin-Based Catalysts

and 8Mn, following the series 8Co > 8Fe > 8Mn (Scheme 5). They also observed that the catalyst 8Co could be recovered by simple filtration and reused without significant loss of activity for nine cycles.112 Following this work, the same authors113 prepared a family of cobalt, iron, and manganese metalloporphyrins 10−12 immobilized on silica-gel-grafted copolymer poly(N-vinylimidazole-co-styrene) through an axial coordination reaction (Scheme 5). Similarly, the catalytic performance of the catalyst was evaluated in the oxidation of ethylbenzene at 120 °C under 0.1 MPa pressure, using a 1.5 × 10−2 mol% catalyst load, with the trend 10Co > 10Fe > 10Mn (25%, 22%, and 20% conversions, respectively). This trend was similar to that previously reported by the same authors, regarding the evaluation of 8Fe, 8Co, and 8Mn,112 where no influence of axially coordinated imidazole was found, when compared with pyridine. The authors then evaluated the effect of porphyrin structure of Co(II) catalysts and found that 11Co, bearing nitro groups, was the catalyst with best performance (31% conversion). This catalyst could also be recovered by filtration and reused without significant loss of activity for 10 cycles. Huang 114 linked tetrakis(4-carboxyphenyl)porphyrin manganese(III) chloride onto powdered chitosan through acylation, obtaining catalyst 13Mn (Scheme 5). Powdered chitosan with a high degree of deacetylation was found to be a suitable carrier, having enough amino groups for the linkage of manganese(III) porphyrin. The researchers found that the

Under the same reaction conditions and using 3Co as catalyst,115 the study was extended to evaluate the effect of electron-withdrawing vs -donating groups on the benzyl ring. The researchers observed that the best activities and selectivity for ketone were achieved with strong electron-withdrawing groups, following the order methoxy < hydrogen < bromo < acyl < nitro (conversion 9% to 53%, respectively). Furthermore, the conversions of substrates bearing parasubstituents were much higher than those of substrates bearing similar ortho-substituents (ortho-bromo and ortho-nitro substituents). Zhao and Wu103 reported the synthesis of a metal−organic framework (MOF), in which Cu(II) meso-tetrakis(3,5dicarboxyphenyl)porphyrinate (14Cu) was immobilized onto the porous framework, by reaction of meso-tetrakis(3,5dicarboxyphenyl)porphyrin with copper(II) acetate to form 14Cu in situ, in a mixed solvent of DMF and nitric acid for 1 week, which allowed the coordination polymer to form. The new MOF 15Cu (Figure 4) was then applied in aerobic oxidation of arylalkanes using O2 as oxidant for 24 h at 50 °C (Scheme 7), where up to 99% yield and complete selectivity were obtained for the corresponding ketones, using Nhydroxyphthalimide (NHPI) as radical generator and polyoxometallate [WZn{Co(H2O)}ZnW9O34)2]12 as co-catalyst. 10788


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In general, and given the reports available so far, heterogeneous catalysts seem to be the educated choice for oxidation of C−H bonds in alkylbenzene substrates. In most cases, the yields when using homogeneous systems are comparable to those when using heterogeneous ones. Nevertheless, the metal−organic framework heterogeneous MOF 15Cu catalyst was revealed to be the most efficient for this type of reaction, providing complete selectivity for the corresponding ketones. 2.1.2. Cycloalkanes. A synthesis and characterization of iron μ-oxo porphyrins 4Fe and 5Fe (Figure 4) and 16Fe−19Fe (Figure 5) and their application in catalytic oxidation of cycloalkanes using molecular oxygen was reported by Tabor (Scheme 8).116 The effect of substituents (electron-donating or electronwithdrawing) on the catalytic activity was evaluated, using cyclooctane as model substrate for 6 h at 120 °C with O2 pressure of 1 MPa. All synthesized iron μ-oxo complexes were catalytically active in the oxidation of cyclooctane by molecular

Scheme 7. Catalytic Oxidation of Alkyl Aromatics Catalyzed by Heterogeneous Catalyst MOF 15Cu

To rationalize the effect of the central metal and the porphyrin structure, the values of TON and TOF for the oxidation reactions of alkylbenzenes, exclusively under homogeneous systems, are presented in Table 1. Independently of the substrate, porphyrin structure, and reaction conditions in the oxidation of alkylbenzenes, the central metal was the most relevant issue for the catalyst activity (Co(II) > Mn(III) > Fe(III)). The Co(II) complexes were the best and most active catalysts, with TONs up to ∼63 500, as reported by Zhou and Hu (Table 1, entry 14).109 Table 1. TON and TOF Values for Oxidation of Alkylbenzenes

product

TONa

TOFa

p-cresol p-cresol p-cresol p-cresol p-cresol p-cresol

p-hydroxybenzaldehyde p-hydroxybenzaldehyde p-hydroxybenzaldehyde p-hydroxybenzaldehyde p-hydroxybenzaldehyde p-hydroxybenzaldehyde

12 915 14 677 21 084 23 684 15 045 15 124

1 291 1 467 2 108 2 368 1 504 1 512

104 104 104 104 104 104

1Fe 2Fe 1Co 1Mn

o-cresol o-cresol o-cresol o-cresol

o-hydroxybenzaldehyde o-hydroxybenzaldehyde o-hydroxybenzaldehyde o-hydroxybenzaldehyde

575 65 110 117

72 8 14 15

104 104 104 104

11

3Fe

p-xylene

19 924

4 427

109

12

6Fe

p-xylene

42 720

9 493

109

13

3Co

p-xylene

35 504

11 834

109

14

6Co

p-xylene

63 546

18 156

109

15

3Mn

p-xylene

28 635

7 158

109

16

6Mn

p-xylene

52 444

13 111

109

17

7Mn

p-xylene

p-methylbenzaldehyde p-methylbenzyl alcohol p-methylbenzoic acid p-methylbenzaldehyde p-methylbenzyl alcohol p-methylbenzoic acid p-methylbenzaldehyde p-methylbenzyl alcohol p-methylbenzoic acid p-methylbenzaldehyde p-methylbenzyl alcohol p-methylbenzoic acid p-methylbenzaldehyde p-methylbenzyl alcohol p-methylbenzoic acid p-methylbenzaldehyde p-methylbenzyl alcohol p-methylbenzoic acid p-methylbenzaldehyde p-methylbenzyl alcohol p-methylbenzoic acid

13 653

2 730

110, 111

18 19 20 21

3Fe 4Fe 3Co 3Mn

p-nitroethylbenzene p-nitroethylbenzene p-nitroethylbenzene p-nitroethylbenzene

36 349 23 637 48 388 40 758

3 029 1 969 4 032 3 398

115 115 115 115

entry

catalyst

1 2 3 4 5 6

1Fe 2Fe 1Co 2Co 1Mn 2Mn

7 8 9 10

substrate

p-nitroacetophenone p-nitroacetophenone p-nitroacetophenone p-nitroacetophenone

ref

a

Values calculated by us; Turnover number (TON) = mol products per mol catalyst; Turnover frequency (TOF) = TON/h. 10789


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three cycles; however not showing how re-utilization was performed. Guo117 evaluated the effect of metalloporphyrin 3Co (Figure 5) on the aerobic oxidation of this hydrocarbon in an industrial-scale trial, using extremely low concentrations (2 × 10−4 mol%) of metalloporphyrin catalysts at 145 °C and under 0.8 MPa air pressure (Scheme 9). One of the main

Scheme 8. Catalytic Oxidation of Cycloalkanes Catalyzed by Iron μ-Oxo Dimer Porphyrins

Scheme 9. Metalloporphyrin-Catalyzed Cyclohexane Oxidation with Air

oxygen, with 19Fe (bearing 20 fluorine groups) being the best one, giving 55% yield of cyclooctanone plus cyclooctanol. The researchers also observed that the catalytic performance of iron μ-oxo dimer complexes was not very dependent on the nature of its substituents, as 16Fe (bearing methyl groups) also provided the ketone plus alcohol in similar yields (48%). Moreover, the authors claimed that the catalyst 5Fe could be reused with only a small decrease of catalytic activity up to

conclusions was that there was no difference in the catalytic performance of metalloporphyrin 3Co between small- and

Figure 5. Homogeneous and heterogeneous metalloporphyrin catalysts for C−H oxidation of cycloalkanes. 10790


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ACS Catalysis industrial-scale trials. When compared with industrial noncatalyzed cyclohexane oxidation with air (at a temperature of 165 °C and air pressure of 1.2 MPa), the catalyzed reaction required lower temperatures (145 °C) and air pressures (0.8 MPa), and the cyclohexane conversion increased from 4.8% to 7.1% (significant at an industrial scale), together with an increase in cyclohexanone yield (77% to 87%), using 1−5 ppm concentration of metalloporphyrin catalyst. These experimental improvements led the authors to conclude that this procedure significantly increases the low conversion rates and the low yields faced by the cyclohexane oxidation industry over the past decades. The authors also observed that the cyclohexane conversion was very low at temperatures below 120 °C, and, interestingly, when high temperatures (145 °C) and short reaction times (1.5 h) were used, the selectivity for the production of cyclohexanol + cyclohexanone increases, when compared for instance with reaction carried out at 125 °C, or with longer times, as the products started to be transformed into non-quantified polymers.117 The same authors118 also reported a systematic study on the effect of cobalt-based catalysts structure, using cobalt isooctanoate, 20Co, and 4Fe (Figure 5) as catalysts on the aerobic oxidation (0.8 MPa O2) of cyclohexane (Scheme 10)

The same authors120 also tested metalloporphyrins 6 and 21 (Figure 5) in the catalytic oxidation of cyclohexane, carried out in a stainless steel autoclave at 140 °C under the air pressure of 0.7 MPa, with a catalyst concentration of 4 × 10−4 mol% and a reaction time optimized for 4.5 h (Scheme 11). They compared the performance of catalysts 6Fe, 6Co, and 6Mn, and 21Fe, 21Co, and 21Mn, observing that 21Co was the best catalyst, displaying a conversion of 27%. Regarding selectivity, all catalysts showed high values ranging from 87 to 91% for a mixture alcohol and ketone; however, catalysts 21 showed better alcohol/ketone ratios, ranging from 1.0 to 1.3. The aerobic oxidation of cyclohexane with O2 catalyzed by 20Mn (Figure 5) and benzoic acid as co-catalyst was also investigated (Scheme 12).95 Using a catalyst load of 7 × 10−4

Scheme 10. Effect of Cobalt Catalyst Structure on the Aerobic Oxidation of Cyclohexane

mol%, co-catalyst (30 mol%), 140 °C, continuous O2 pressure of 1.4 MPa in neat cyclohexane for 3 h, the main oxidation products were adipic acid, cyclohexanone, and cyclohexanol. No catalyst reuse or degradation studies were presented. Huang121 described the synthesis of metalloporphyrins (M = Fe(III), Co(II) or Mn(III)) covalently immobilized on styrene−methylacrylic acid copolymer microspheres (22Fe, 22Co, and 22Mn, Figure 5) and their application in catalytic hydroxylation of cyclohexane using O2 as oxidant (Scheme 13). The styrene−methylacrylic acid copolymer microspheres

Scheme 12. Aerobic Catalytic Oxidation of Cyclohexane Using a Manganese Porphyrin Derivative

at hundreds gram scale (270 g) and catalysts in 1 ppm, for 3 h at 150 °C. The authors observed a moderate conversion (up to 15.4%) and a good selectivity (95.6%) for the mixture of cyclohexanol and cyclohexanone (KA oil) in all cases. Moreover, the authors also observed that the bis-iron porphyrin complex (4Fe), traditionally considered less active for hydrocarbon oxidation, presented a relevant performance at 155 °C, achieving high selectivity for KA oil (80%) with average conversion (14%). Hu119 studied the influence of structure and central metal of a family of metalloporphyrins (1Cu, 1Zn, 1Ni, 6Cu, 6Zn, and 6Ni (Figure 4) plus 6Co, 20Co, 20Cu, 20Zn, and 20Ni (Figure 5)) in the oxidation of cyclohexane using air as oxidant and in the absence of any co-catalyst or co-reductant, using air pressure of 0.8 MPa and 2 × 10−5 mol/L metalloporphyrin for 4 h at 145 °C (Scheme 11). At first, the authors concluded that

Scheme 13. Magnetic Nanocomposites as Catalysts for the Oxidation of Cyclohexane

were synthesized by reacting styrene, divinylbenzene, and αmethylacrylic acid. Then, the microspheres containing carboxylic acid groups were activated with thionyl chloride, followed by addition of the corresponding metalloporphyrin. The catalytic hydroxylation reaction was performed using cyclohexane (5.55 mmol) as substrate, ascorbate and thiosalicylic acid (3.0 mmol and 4.0 × 10−2 mmol) as coreductants, acetone/water 9:1 (10 mL) as solvent mixture, and O2 (101 KPa) as oxidant. The authors observed conversion up to 60% (22Mn) with an excellent selectivity for the mixture of cyclohexanol and cyclohexanone. Moreover, these catalysts have enhanced catalytic capabilities and extended catalytic lifetimes compared to the corresponding non-supported metalloporphyrins, being able to be reused for several recycles. Attempting to improve the recyclability of metalloporphyrinbased catalysts, the same authors122 reported the synthesis of magnetic nanocomposites 23Mn−25Mn (Figure 5), bearing manganese porphyrin derivatives, prepared by immobilization of Mn(III) porphyrins appending p-OCH3, p-H, and p-Cl phenyl substituents onto magnetite by cross-copolymerization

Scheme 11. Aerobic Catalytic Oxidation of Cyclohexane Using Metalloporphyrin Derivatives as Catalysts and Molecular Oxygen as Oxidant

cobalt-based catalysts showed the highest activity and that, in general, metallo-deuteroporphyrins (Nature-based porphyrin) performed better than meso-substituted porphyrins, reaching conversions up to 19% (6Co). The authors also found that meso-substituted porphyrin catalysts bearing electron-withdrawing groups showed better activity, 20Co being the best catalyst. 10791


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810 000) and yields (up to 23%) for ketone and alcohol at 150 °C and 0.7 MPa. Therefore, they could be reused 10 times without loss of activity and selectivity, which was attributed to stronger electrostatic coordination of ZnO to the iron porphyrin and improved dispersion of the iron porphyrin by ZnO. Huang125,126 also reported the oxidation reaction of cyclohexane using molecular oxygen, but in this case a zinc sulfide-supported iron meso-(4-carboxyphenyl)porphyrin (30Fe, Figure 5) was used as catalyst (Scheme 15). The oxidation of cyclohexane was performed using molecular oxygen (0.6−1.1 MPa) as oxidant in the absence of solvents and co-reductants. Moreover, oxidation process was optimized with respect to the effects of oxygen pressure, reaction temperature, amount of 30Fe, and reaction time. The hybrid heterogeneous catalyst exhibited good stability and good activity for aerobic cyclohexane oxidation, yielding conversion up to 65% and a mixture of alcohol and ketone up to 47%. Moreover, the authors described the reuse of the catalyst up to four times without significant loss of activity. Gao127 reported the immobilization of cationic metalloporphyrins onto cross-linked polystyrene microspheres (CPS microspheres) obtaining catalysts type 31 (Figure 5). To synthesize the catalysts, first the chloromethylated cross-linked polystyrene microspheres were synthesized by self-copolymerization. These microspheres were then reacted with 4hydroxybenzaldehyde to form the corresponding benzaldehyde adduct, which was then reacted with 4-(dimethylamino)benzaldehyde, producing, after workup and methyl iodide cationization, the desired catalyst 31. This catalyst was further composited with heteropolyanions by mutual electrostatic interaction with phosphotungstic (PW) acid and phosphomolybdic (PMo) acids, yielding heterogeneous metalloporphyrin/ heteropolyanion composites 32 and 33, respectively (Figure 5). These catalysts (1.6 × 10−2 mol%) were evaluated in the oxidation of cyclohexane using O2 at atmospheric pressure, fixed flow rate, without solvent, under moderate temperature (40 °C), and the authors observed that cyclohexane conversion increased in the order 31Co > 31Mn > 31Fe (Scheme 16).127

of the porphyrin acrylate with vinylbenzene and divinylbenzene (Scheme 13). The catalytic activity as biomimetic catalysts to promote cyclohexane hydroxylation was evaluated (1 equiv) with molecular oxygen, at atmospheric pressure, using the catalysts at 1.5 × 10−6 mol% for supported and 2.3 × 10−5 mol% for homogeneous systems and a mixture of ascorbate (0.55 equiv) and thiosalicylic acid (0.007 equiv) as co-reductants in acetone/water (9:1) mixture as solvent, at 30 °C. Several runs were performed, and the catalysts were recovered by easy separation using an external magnetic field and reused under identical conditions for five runs.122 The beneficial effect of immobilizations was corroborated by the fact that the non-supported manganese porphyrin acrylates displayed a total turnover number (TON) of 3.44, while the supported catalysts 23−25 (Mn) presented TONs 215−308 times larger. Nanocomposite 23Mn, bearing electron-donating p-OCH3 groups at the porphyrin’s peripheral phenyl rings, had the best performance, with TONs above 1000 in all 5 runs, while 24Mn (non-substituted phenyl rings) and 25Mn (p-Clsubstituted phenyl rings) showed TONs of ∼930 and ∼740, respectively. Regarding selectivity, the behavior of the catalysts was similar, showing favorable ratios for cyclohexanol formation. Nanocomposite 24Mn, in this case, showed an averaged higher ratio cyclohexanol/cyclohexanone of ∼3.8, while the other catalysts showed ratios ∼2.5. In addition, the same authors123 reported the synthesis of three types of silica microspheres containing Mn(III) porphyrins bearing p-CH3, p-H, and p-Cl phenyl substituents yielding 26−28 (Figure 5) and tested them in the hydroxylation of cyclohexane, under the conditions described above, but using higher mol% of catalysts (∼6 × 10−3 mol%) (Scheme 14). Similarly to the previous study, nanocomposite Scheme 14. Silica Microsphere-Supported Metalloporphyrins for Dioxygen-Mediated Cyclohexane Oxidation

Scheme 16. Cross-Linked Polystyrene Microspheres for Aerobic Cyclohexane Oxidation

26Mn, bearing electron-donating CH3 groups, showed better catalytic performance, reaching an average TON of ∼78, while 27Mn and 28Mn displayed average TONs of 66 and 45, respectively. Likewise, the catalyst 26Mn could be easily recovered from the catalytic system and reused under identical conditions for four runs. W e i 1 2 4 reported the immobilization of meso(pentafluorophenyl)porphyrin iron chloride onto zinc oxide by adsorption (Scheme 15). The new hybrid material 29Fe (Figure 5) was then employed as catalyst in the oxidation of cyclohexane using molecular oxygen as oxidant in the absence of solvents and co-reductants. This heterogeneous catalyst proved to be stable, with very high turnover numbers (up to

The microspheres containing immobilized cationic porphyrin 31Co showed cyclohexane conversion of 33% after 8 h (TON = 1961), along with a remarkable selectivity to cyclohexanol of nearly 100%. Comparison of the performance of 31Co with the related heteropolyanionic composites, 32Co and 33Co, allowed the authors to conclude that both 32Co and 33Co were more active than 31Co, reaching TON values of 3067 and 2784, respectively. To examine catalyst stability, recycling experiments for the composite catalyst 32Co were also conducted, having recyclability up to six runs, without leaching. A sustainable hydroxylation process of p-menthane in absence of solvents and additives under ambient pressure was reported by Lu,128 using homogeneous metalloporphyrins

Scheme 15. Oxidation of Cyclohexane Catalyzed by Immobilized Iron(III) Porphyrins

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concentration of catalysts. The authors also observed, as expected, that tertiary C−H bonds were more easily oxidized than secondary and primary C−H ones; however, they provided the desired terpineols in quite low yields. Upon the presented reports, heterogenization of catalysts was revealed to be the best strategy as, in general, allheterogeneous catalysts performed more efficiently than homogeneous ones. Within these, iron(III)-containing catalysts performed better than catalysts complexed with other metals with, for instance, 29Fe reaching TONs of 810 000. An important point regards the alcohol/ketone ratio selectivity. In most cases, the known KA oil was obtained as major product; however, in some cases more specific selectivity was obtained, as for instance when catalysts 31−33 were used, where selectivity for alcohols of near 100% were obtained.127 To rationalize the effect of the central metal and the porphyrin structure, the values of TON and TOF for the

as catalysts 6 (Figure 5) and again molecular oxygen as oxidant (Scheme 17). It was found that 6Fe was the most active Scheme 17. Homogeneous Catalytic Aerobic Hydroxylation of p-Menthane with Metalloporphyrins and O2 as Oxidant

catalyst for dihydroterpineols (DHTs), using a pressure of O2 = 0.1 MPa and temperature of 40 °C, following the series 6Fe > 6Co > 6Mn > 6Cu > 6Zn. The yield and selectivity of DHTs (trace, 12.4% yield) were highly dependent on various reaction conditions such as the reaction temperature and the Table 2. TON and TOF Values for Oxidation of Cycloalkanes entry

catalyst

substrate

product

TONa

TOFa

ref

b

1 2 3 4 5 6

4Fe 5Fe 16Fe 17Fe 18Fe 19Fe

cyclooctane cyclooctane cyclooctane cyclooctane cyclooctane cyclooctane

cyclooctanone/cyclooctanol cyclooctanone/cyclooctanol cyclooctanone/cyclooctanol cyclooctanone/cyclooctanol cyclooctanone/cyclooctanol cyclooctanone/cyclooctanol

65 280 55 020b 108 660b 62 760b 76 740b 122 640b

10 880b 9 170b 18 110b 10 460b 12 790b 20 440b

116 116 116 116 116 116

7 8 9 10 11 12 13

1Co 3Co 6Co 6Co 20Co 20Co 21Co

cyclohexane cyclohexane cyclohexane cyclohexane cyclohexane cyclohexane cyclohexane

cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol adipic acid/cyclohexanone cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol

29 676b 308 800b 85 147b 85 147b 130 746 55131b 61 728b

7 419 − 28 382 24 327b 43 582 13 782 13 717b

119 117 119 120 118 119 120

14 15 16 17 18 19

4Fe 6Fe 21Fe 1Cu 6Cu 20Cu

cyclohexane cyclohexane cyclohexane cyclohexane cyclohexane cyclohexane

adipic acid/cyclohexanone cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol

131 100 27 639b 43 532b 34 558b 55 798b 51 241b

43 700 5 527b 8 706b 8 639 13 949 12 810

118 120 120 119 119 119

20 21 22

1Zn 6Zn 20Zn

cyclohexane cyclohexane cyclohexane

cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol

28 037b 60 135b 52 297b

7 009 15 033 13 074

119 119 119

23 24 25 26

1Ni 6Ni 20Ni 6Mn

cyclohexane cyclohexane cyclohexane cyclohexane

cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol cyclohexanone/cyclohexanol

27 162b 37 506b 50 602b 36 622b

6 790 9 376 12 656 9 155

119 119 119 120

27 28 29

21Mn 6Mn 22Mn

cyclohexane p-menthane cyclohexane

cyclohexanone/cyclohexanol dihydroterpineols cyclohexanone/cyclohexanol

50 442b 6 616 31.5b

11 209b 389 10.5

120 128 121

30 31 32 33

6Fe 6Co 6Cu 6Zn

p-menthane p-menthane p-menthane p-menthane

dihydroterpineols dihydroterpineols dihydroterpineols dihydroterpineols

9 087 8 192 4 857 4 630

535 482 286 272

128 128 128 128

a

Values calculated by us, unless noted otherwise; Turnover number (TON) = mol products per mol catalyst; Turnover frequency (TOF) = TON/ h. bValue reported by the authors. 10793


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Ji135 also reported the immobilization of cationic mesotetrakis(1-methyl-4-pyridyl) metalloporphyrins into montmorillonite interlayers obtaining catalysts of type 34 (Figure 6). The authors evaluated the catalysts (10−2 mol%), for the epoxidation of olefins, isobutyraldehyde (3 equiv) as coreductant, O2 (bubbling) as oxidant, acetonitrile as solvent, for 3 h at room temperature (Scheme 19). Using cyclohexene as

oxidation reactions of cycloalkanes in the homogeneous catalytic system were calculated and are presented in Table 2. In the oxidation of cycloalkanes, for instance using μ-oxo iron(III) complexes as catalysts, a significant effect of the porphyrin structure was observed, with the best TON being obtained for the (pentafluorophenyl)porphyrin 19Fe (TON = 122 640, Table 2, entry 6).116 Regarding the oxidation of cyclohexane, the influence of the central metal was more pronounced than the porphyrin structure. Independently from the structures of porphyrin catalysts used, Co(II) tetraphenylporphyrin 3Co is the best catalytic system (Table 2, entry 8, TON = 308 800).117 2.2. Olefin Oxidation. Ji132,133 reported the use of iron(III) 3Fe, cobalt(III) 3Co, manganese(III) 3Mn, and ruthenium(III) 3Ru porphyrins (Figure 4) as homogeneous catalyst for the oxidation of olefins using cyclohexene as model substrate (Scheme 18).

Scheme 19. Montmorillonite-Supported Metalloporphyrins as Cyclohexene Oxidation Catalysts

Scheme 18. Oxidation of Olefins Catalyzed by Metalloporphyrins in the Presence of O2: (a) Cyclohexane without Co-catalyst, (b) Cyclohexane with Cobalt Diacetate as Co-catalyst, and (c) Propylene with Benzaldehyde as Cocatalyst

model compound, the authors observed that epoxide was the main product, along with little amount of allylic oxidation products cyclohex-2-en-1-one and 2-cyclohexen-1-ol. Manganese porphyrin 34Mn was the best catalyst, displaying excellent activity (>95%) and selectivity for epoxide up to 95%. Catalyst 34Mn was further tested for the epoxidation of a series of olefins, under the same reaction conditions (Scheme 19).135 Most substrates were easily converted to the corresponding epoxides with high conversion rate and epoxide selectivity for higher substituted double bonds ((+)-limonene). Moreover, the stability of catalyst 34Mn was evaluated using sequential epoxidation reactions using cyclohexene as model substrate. The catalyst was recovered by centrifugation, filtration, washed with acetonitrile, and dried before use in the next run. The authors observed no significant leaching and no loss of activity or selectivity for five consecutive runs.135 Rayati136 reported the synthesis of catalyst 35Fe (Figure 6), carried out by covalent anchoring of meso-tetrakis(4hydroxyphenyl)porphyrinate iron(III) chloride onto multiwalled carbon nanotubes (Scheme 20). The catalyst was used in aerobic oxidation of olefins (isobutyraldehyde as coreductant) to their corresponding epoxides, and up to 100% conversion and selectivity was observed. The heterogeneous nanocatalyst was re-utilized for seven cycles without leaching and loss of activity. Wu137 developed the new 3D covalent porphyrinic framework 36Co (Figure 6), synthesized by condensation of fourbranched tetraphenylamine porphyrin and the trigonal 1,3,5triformylbenzene, based on the principle of reticular chemistry, followed by metalation with cobalt(II) acetate (Scheme 21). This hybrid material catalyst was evaluated in epoxidation reaction of olefins under mild conditions, in which >99% conversion, 93% epoxide selectivity, TON = 29 215, and TOF = 3434 h−1 were observed, using styrene as model substrate. The authors extended this work to several other substrates, seeking higher conversions toward epoxide formation for cyclic olefins. Furthermore, the new heterogeneous catalyst exhibited higher stability than its homogeneous counterparts and could be reused up to 15 cycles without loss of activity/selectivity. Wu129 reported the synthesis of a hybrid material, 37Mn (Figure 6; inorganic polyoxometalates (POMs) + metalloporphyrins), and its application as heterogeneous catalyst in

The authors evaluated the effect of central metal in the epoxidation of cyclohexene, using the metalloporphyrins 3 as catalysts (1 × 10−4 mol%), isobutyraldehyde (5 equiv) as coreductant, O2 as oxidant, dichloromethane as solvent, at room temperature, for 4 h (Scheme 18a).132 Among them, the metalloporphyrin 3Mn revealed to be the best catalyst, with 99% conversion and 99% epoxide selectivity. In addition, a change in selectivity was observed when cobalt acetate was used as co-catalyst in combination with 3Mn (1.67 × 10−4 mol%), O2 (0.4 MPa), in acetonitrile, at 80 °C for 12 h. Under these reaction conditions, the selectivity for epoxide diminished (16%) and the amount of allylic oxidation products increased significantly (58 and 9% for cyclohex-2-en-1-one and 2-cyclohexen-1-ol, respectively; Scheme 18b).133 The same authors134 reported the investigation of the gas− liquid phase catalytic epoxidation of propylene derivatives, using O2 as oxidant, manganese complex of meso-tetraphenylporphyrin 3Mn as catalyst, and benzaldehyde as co-reductant. The conversion of propylene was only 38%, and selectivity toward propylene oxide (PO) reached 80% (Scheme 18c), while longer alkenes (1-hexene) gave conversion of 99%, with 81% selectivity for the epoxide. The authors suggested by experimental and computational (DFT) calculations that the mechanism involves the generation of Mn(IV)−oxo active oxygen donor species. 10794


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Figure 6. Homogeneous and heterogeneous metalloporphyrin catalysts for oxidation of olefins. The structure drawing of 37Mn was adapted with permission from ref 129. Copyright 2016 American Chemical Society. The structure drawing of 38Mn was adapted with permission from ref 130. Copyright 2015 Elsevier. The structure drawing of 39Fe was adapted with permission from ref 131. Copyright 2015 American Chemical Society.

Scheme 20. Catalytic Epoxidation of Olefins by an Fe(III) Porphyrin Supported on Multi-Walled Carbon Nanotubes Using Molecular Oxygen

Scheme 21. Aerobic Epoxidation of Olefins Catalyzed by Covalent Porphyrinic Framework

epoxidation reactions (Scheme 22). This hybrid material was developed by a “step-by-step” aggregation strategy, starting with the reaction of the POM units with metal ions to bind metal nodes on their surfaces, followed by the reaction of the resulting POM derivatives with metalloporphyrin, resulting in the hybrid materials. These experiments demonstrated that the hybrid material was able to catalyze the oxidation of diverse 10795


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ACS Catalysis Scheme 22. Catalytic Epoxidation Reaction Catalyzed by Metalloporphyrin−POM Hybrid Material

Scheme 24. Catalytic Epoxidation Reaction of Olefins Using MOF 39Fe

epoxide ring-opening, yielding the protected 1,2-aminoalcohol with full conversion. The authors recovered the catalyst by simple centrifugation (Scheme 24). The product, a protected 1,2-aminoalcohol, was selectively formed with high efficiency. This regioselectivity was promoted by the concerted presence of Fe-decorated Hf6 nodes and the Fe-porphyrin struts. This report is an example of concurrent orthogonal tandem catalysis using a recyclable heterogeneous hetero-bimetallic catalyst. Hosseini-Monfared138 reported the immobilization of manganese tetra(4-carboxyphenyl)porphyrin onto the chiral surface of magnetite nanoparticles coated with tartaric acid. The new heterogeneous catalyst 40Mn (Figure 7) was applied in the epoxidation reactions of pro-chiral olefins using molecular oxygen as oxidant, again using isobutyraldehyde as co-reductant and acetonitrile as solvent at temperature of 100 °C for 8 h (Scheme 25). The reaction showed good

olefins, with conversion up to 97%, high epoxide selectivity (up to 99%), high turnover number (up to 220 000), and high turnover frequency (up to 22 000 h−1). Moreover, 37Mn could be reused six times with almost no loss of activity/selectivity. Bouchard130 also synthesized MOF-type catalysts, 38Mn (Figure 6), containing a manganese(III) porphyrin as template and MOF [Zr6O4(OH)4(MgC48H24O8N4Cl)3] (Scheme 23). Scheme 23. Epoxidation of olefins using manganese porphyrin-zirconium MOF catalysts

Scheme 25. Aerobic Asymmetric Oxidation of Olefins Catalyzed by Metalloporphyrin Immobilized onto Magnetic Nanoparticles

The catalyst was prepared by reacting Mn(III) meso-tetra(4carboxyphenyl)porphyrinato chloride with zirconyl chloride octahydrate in DMF, under ultrasound. Upon acetic acid addition and further heating, the new zirconium MOF 38Mn was obtained and applied in alkene epoxidation at mild conditions (25 °C for 2.5−4 h) using O2 as oxidant, showing minimal deactivation over long periods and maintaining its structure and activity (70−97% conversion) after multiple catalytic cycles (up to five cycles). The catalyst also showed chemical stability with respect to different alkenes tested. Moreover, the kinetic studies of styrene epoxidation are in agreement with theoretical and experimental studies of homogeneous reactions with the same porphyrin unit, suggesting that the heterogeneous catalyst operates with a mechanism similar to that of its homogeneous counterpart. Porphyrin meso-tetra(4-carboxyphenyl)porphyrin was also used as structural motif for the construction of Hf6 heterobimetallic metal organic framework Hf6-MOF 39Fe (Figure 6).131 This catalyst was synthesized in several steps. First, the Hf node was prepared and then reacted with meso-tetra(4carboxyphenyl)porphyrinato iron(III) chloride in DMF for 2 days, providing 39Fe, which was then applied in tandem epoxidation/ring opening of styrene. The authors mixed in the same autoclave the catalyst, Hf6-MOF 39Fe, styrene and isobutyraldehyde as co-reductants, and azidotrimethylsilane (Scheme 24). The autoclave was pressurized with O2 (0.5 MPa) as oxidant and acetonitrile as solvent, for 10 h at 80 °C. The catalyst Hf6-MOF 39Fe was able to transfer oxygen to form the epoxide and also to act as Lewis acid to catalyze the

conversions (68−100%), reasonable to good selectivity for epoxide (47−100%), and variable enantioselectivity (11− 100%), depending from the olefin structure (terminal, cyclic, and aromatic olefins), the best results being obtained with cyclic olefins. The catalyst showed little deactivation with time, was easily recovered by magnetic filtration, and could be reused four times with little loss in activity and selectivity. The same authors139 reported another magnetic hybrid metalloporphyrin catalyst, 41Mntart (Figure 7), prepared by covalent attachment of a manganese complex of meso-tetra(4pyridyl)porphyrin onto magnetic nanoparticles and stabilized with chiral L-(+)-tartaric acid (tart), for enantioselective epoxidation using molecular oxygen as oxidant and also isobutyraldehyde as co-reductant. The immobilized cationic system showed high activity (up to 100%) and selectivity (up to 90%) for the oxidation of olefins (cis- and trans-stilbene, styrene, 1-decene, and 1-phenyl-1-cyclohexene) to give 10796


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Figure 7. Heterogeneous metalloporphyrin catalysts based on magnetic nanoparticles for oxidation of olefins.

optically active epoxides (enantiomeric excess up to 97%) (Scheme 26). The catalyst was reused for several runs using styrene as substrate without loss of activity and keeping the selectivity epoxide at 100%.

was evaluated in the epoxidation of olefins, using molecular oxygen (bubbling) as oxidant, isobutyraldehyde as coreductant, and cyclooctene as model substrate, at temperature of 100 °C for 90 min (Scheme 27). The heterogeneous system

Scheme 26. Aerobic Asymmetric Oxidation Olefins Catalyzed by Manganese Metalloporphyrin Immobilized onto Magnetic Nanoparticles

Scheme 27. Recyclable Hybrid Manganese(III) Porphyrin Magnetic Catalyst for Olefin Epoxidation

Pereira140 reported the synthesis and characterization of a non-symmetric Mn(III) meso-tetraphenylporphyrinate and their immobilization onto magnetic nanoparticles previously functionalized with 3-cloropropyltrimethoxysilane. The monoaminated porphyrin was covalently linked to the nanoparticles via nucleophilic substitution reaction, giving the nanocomposite 42Mn (Figure 7). This heterogeneous catalyst

showed high conversion (99%) and selectivity for epoxide (98%). Furthermore, it was easily recovered with an external magnetic and reused in five consecutive runs without loss of activity or epoxide selectivity. The magnetic catalyst 42Mn was also used in the epoxidation of other olefins, namely derived from natural-based cores with high biological relevance, such 10797


Review

ACS Catalysis

hexen-1-ol, 29%; and 2-cyclohexen-1-one, 55%). The reutilization of the catalysts was not described since partial degradation of the catalyst was observed. To rationalize the effect of the central metal and the porphyrin structure, the values of TON and TOF for the oxidation reactions of cycloalkanes in the homogeneous catalytic system were calculated and are presented in Table 3. Concerning the epoxidation of olefins, it can be generally concluded that both Mn(III) and Fe(III) metal porphyrins are highly active catalysts (TON up to 990 000).130,142 Summing up, olefinic substrates, when oxidized, usually give epoxides or hydroxylation products (namely alcohols and their oxidized ketones). Manganese(III)-based catalysts are usually the best ones to produce epoxides. Once again heterogenization appears to be the best strategic tool for this type of reactions. Heterogeneous manganese catalysts proved to be very efficient for epoxide preparation, while iron(III) and Cu(II) ones were most active for the preparation of allylic oxidation products. 2.3. Alcohol Oxidation. Berner146 reported the synthesis of thiol-functionalized cobalt porphyrin 46Co (Figure 8) and its linking by self-assembling cobalt porphyrin monolayers onto gold nanoparticles surfaces, yielding 46Co-Au (Figure 8). The authors first evaluated the homogeneous catalyzed oxidation of hydroquinone using metalloporphyrin 46Co (1.7 × 10−4 to 4.2 × 10−1 mol%) in acetic acid, under O2 atmosphere (0.1 MPa), at 25 °C (Scheme 30). The main conclusions were that, for low catalyst loadings, conversions were very low, while with higher catalyst concentration (4.2 × 10−1 mol% loading), TON numbers raised. However, the authors observed an abrupt drop in conversion after about 10 h, which was attributed to catalyst inactivation, due to decomposition. The same tests were then carried out for the heterogeneous system 46Co-Au,146 under similar reaction conditions. Each porphyrin molecule produced more than 10 000 benzoquinone molecules during the experiment (about 350 h), reaching values at least 100 times higher than that of its homogeneous congener, indicating that no inactivation was observable. Hassanein and co-workers147 prepared heterogenized catalyst 47Co (Figure 8) by ionic linking of meso-(4sulfonatophenyl)porphyrinate cobalt(II) on Amberlite ionexchange resin. The authors used the catalyst 47Co for the biomimetic auto-oxidative coupling of 2-aminophenol to produce 2-aminophenoxazin-3-one, using O2 pressure of 0.1 MPa in a CH3OH/water solution (5% v/v) (Scheme 31). Using sodium borate and sodium phosphate buffers, the autooxidation of 2-aminophenol was studied at 7 < pH < 11, reaching an optimum rate at pH 9.0. At this pH, the amount of catalyst used was also tested, and 1 mol% of 47Co was the best substrate/catalyst ratio to produce 2-aminophenoxazin-3-one in high yields. Moreover, the stability of the heterogeneous catalyst was tested by recycle/reuse evaluation, showing no loss of activity after six successive runs. Metalloporphyrin-based polymer 48Mn (Figure 8) was prepared by Buchwald−Hartwig aromatic amination using pphenylenediamine and manganese tetraphenylporphyrin as building blocks148 (Scheme 32). The catalyst was evaluated in the aerobic oxidation of alcohols, under mild conditions, using acetonitrile as solvent, and isobutyraldehyde as co-reductant, at 40 °C, exhibiting high catalytic activity and selectivity for aldehyde. Under these reaction conditions, oxidation of benzyl alcohols gave selectivity to corresponding benzaldehydes in the

as terpene and steroid derivatives, with conversion and yield of up to 99% and 96%, respectively (Scheme 27). Pereira and Calvete141 reported a different approach for the synthesis of copper porphyrins immobilized onto magnetic nanoparticles. The catalysts 43Cu and 44Cu (Figure 7) were prepared by covalent linking of copper meso-tetraphenyl-βnitro-porphyrinate bearing fluorine or chlorine atoms at the ortho-positions of the phenyl rings through β-substitution pathway with the 3-aminopropyl-3-methoxysilane previously linked onto the silica-coated magnetite. These catalysts (2 × 10−6 mol%) were tested in the oxidation of cyclohexene in the presence of O2 (0.4 MPa) at 100 °C for 4 h (Scheme 28), Scheme 28. Biologically Inspired and Magnetically Recoverable Porphyrinic Catalysts as Hydrocarbon Oxidation Catalysts

yielding cyclohex-2-en-1-one and 2-cyclohexen-1-ol as the main oxidation products, reaching one of the highest TON values so far obtained (∼200 000). A comparative study between homogeneous and heterogeneous oxidation of cyclohexene was described, and the heterogeneous system was revealed to be the most promising concerning stability and reusability of the catalysts. The scope of the reaction was extended to other substrates, namely terpenes, and conversions of 57 and 34% were obtained for α-pinene and β-pinene, respectively, after 21 h of reaction under conditions similar to those described for cyclohexene (Scheme 28). Drain142−144 described the synthesis of organic nanoparticles (45Fe, Figure 7) prepared by the addition of a water− triethyleneglycol mixture to a THF solution of iron(III) mesotetra(pentafluorophenyl)porphyrinate substituted with perfluorinated alkyl chains upon sonication. These organic nanoparticles were evaluated as allylic oxidation catalysts of cyclohexene (Scheme 29), using O2 as oxidant yielding complete selectivity for 2-cyclohexen-1-ol (29%) and 2cyclohexen-1-one (70%). Furthermore, the authors also studied the corresponding homogeneous catalytic system, and lower selectivity was observed (epoxide,16%; 2-cycloScheme 29. Organic Nanoparticles of 5,10,15,20Tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrinato Iron(III) as Catalysts for Oxidation of Cyclohexene

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ACS Catalysis Table 3. TON and TOF Values for Oxidation of Olefins entry

catalyst

substrate

product

TONa

TOFa

1 2 3 4 5

3Mn 3Co 3Fe 3Ru 3Mn

cyclohexene cyclohexene cyclohexene cyclohexene propylene

cyclohexene oxide cyclohexene oxide cyclohexene oxide cyclohexene oxide propylene oxide

990 000 900 000 920 000 850 000 −

247 500 225 000 230 000 212 500 1 004b

ref 133, 133, 133, 133, 134

145 145 145 145

a

Values calculated by us, unless noted otherwise; Turnover number (TON) = mol products per mol catalyst; Turnover frequency (TOF) = TON/ h. bValue reported by the authors.

Scheme 30. Self-Assembled Cobalt−Porphyrin Monolayers on Gold Surfaces for Catalyzed Oxidation of Hydroquinone in the Presence of Molecular Oxygen

Scheme 31. Amberlite-Supported Metalloporphyrin for O2Mediated Catalytic Oxidation of 2-Aminophenol

oxidation reaction system and still had high catalytic activity after several recycles. He149 also prepared supported catalysts 49 (Figure 8), by intercalating metal complexes of meso-(4-sulfonatophenyl)porphyrin [metal = Co(II), Fe(III), and Mn(III)] into ZnAl hydrotalcites (Scheme 33), and investigated them in the

range 95−98%, while aliphatic alcohols produced the corresponding aldehydes in near 100% selectivity, similarly to secondary alcohols, which produced the corresponding ketones with full selectivity. The catalyst also remained stable in the

Figure 8. Homogeneous and heterogeneous metalloporphyrin catalysts for oxidation of alcohols. 10799


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ACS Catalysis Scheme 32. Metalloporphyrin Polymer for Oxidation of Alcohols

Scheme 34. Aerobic Baeyer−Villiger Oxidation Catalyzed by Bifunctional Catalyst Based on Cobalt Tetraphenylporphyrin Intercalated into Zn2Al Hydrotalcite

Scheme 33. Hydrotalcite-Intercalated Metalloporphyrin Catalysts for Alcohol Oxidation

A set of fluorinated iron−porphyrin-conjugated porous polymers (50Fe and 51Fe, Figure 9) were synthesized by Han154 through C−H direct arylation of meso-tetra(2,3,5,6tetrafluorophenyl)porphyrin with 1,4-dibromoaryl compounds catalyzed by Pd(OAc)2 (5 mol%) coordinated with P(tBu)2Me−HBF4 (10 mol%) and K2CO3 as base (Scheme 35). Scheme 35. Fluorinated Porous Conjugated Polyporphyrins as Catalysts for Baeyer−Villiger Oxidation of Ketones, Using O2 and Benzaldehyde as Co-reductant

aerobic oxidation of alcohols in the presence of isobutyraldehyde (3 equiv), at 60 °C, using the catalyst in 1.9 × 10−6 mol% and O2 in a 10 mL/min flow. The catalyst bearing Co(II) as central moiety proved to be the best one, and its activity was extended to the oxidation of several aliphatic and aromatic alcohol derivatives. As expected, the best yields were obtained when benzyl alcohols were used as substrates. The recyclability of the Co(II) catalyst 49Co was also examined in the aerobic oxidation of benzyl alcohol, and no considerable reduction of activity was observed after five runs. In sum, oxidation of alcohols produces typically aldehydes and ketones, depending on the nature of the substrate. In the reported examples, one feature is constant: researchers have always used heterogenized catalysts to oxidize the substrates, with the cobalt(II)-based catalysts showing, in general, the best performances, with respect to efficiency and selectivity. 2.4. Ketone Oxidation. The catalytic oxidation systems metalloporphyrin/O2/co-reductants have been also applied in the Baeyer−Villiger oxidation reaction for transformation of several cyclic ketones to the corresponding lactones under homogeneous148,150 or heterogeneous conditions.151,152 The great interest to develop active and reusable catalytic systems to promote the oxidation of cyclic ketones toward lactones led Yang152 to also evaluate the heterogeneous catalysts 49Mn (Figure 8) to promote the oxidation of cyclopentanone and cyclohexanone with O2 and benzaldehyde as co-reductant, and dichloromethane as solvent at temperature of 60 °C (Scheme 34), reaching up to 98% and 96% conversion, respectively. Furthermore, the catalyst was highly stable and reusable up to 10 times without loss of activity. He153 applied catalyst 49Co (Figure 8) in Baeyer−Villiger oxidation reaction for several cyclic ketones to lactones using benzaldehyde as co-catalyst, at 40 °C, over 7−14 h (Scheme 34). The authors proposed the involvement of peroxybenzoic acid as oxidant, resulting from the in situ oxidation of benzaldehyde with O2, yielding the desired lactones in very high yields.

The obtained materials were chemically and thermally stable, and exhibited a permanent porous nature with high BET specific surface area. The new polymers were used in catalytic transformation of cycloketones into lactones by oxygen through Baeyer−Villiger-type oxidation. The polymer 50Fe exhibited the best catalytic efficiency and recyclability, being able to be reused up to three times with no significant loss of activity. Park151 described the synthesis of highly ordered metal (carboxyphenyl)porphyrin organosilicas prepared from the corresponding tetrakis(carboxyphenyl)porphyrin silsesquioxanes by sol−gel method yielding the hybrid silica−porphyrin materials 52Fe, 52Cu, 52Sn (Figure 9). These materials were evaluated as heterogeneous catalysts for Baeyer−Villiger oxidation of cyclic ketones with O2 and benzaldehyde as coreductant (Scheme 36), 52Fe being the one that reached the best results, yielding 100% conversion after 3 h. Moreover, the catalysts were reused four times without loss of activity. In sum, transformation of ketones to the corresponding lactones have been reported in the past decade, mostly using heterogeneous catalysts. Both iron(III)- and cobalt(II)-based catalysts have shown promise, nevertheless always requiring benzaldehyde as sacrificial co-reductant. 2.5. Oxidation of Miscellaneous Substrates. Other types of substrates have also been evaluated for the production of valuable compounds. For instance, Ji155 reported the oxidation of oximes to carbonyl compounds by molecular 10800


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Figure 9. Heterogeneous metalloporphyrin catalysts for oxidation of ketones.

Scheme 36. Baeyer−Villiger Oxidation of Cyclic Ketones Catalyzed by Tetrakis(carboxyphenyl)porphyrin Silsesquioxanes

Scheme 38. Biomimetic Oxidation of Carbohydrates Catalyzed by Water-Soluble Metalloporphyrins under Aerobic Conditions

oxygen using benzaldehyde as co-reductant and the metalloporphyrin 3Mn as catalyst (Figure 4). In a typical optimized procedure,155 O2 was bubbled into a toluene solution at 50 °C, 1 equiv of oximes, 15 equiv of benzaldehyde, and 1 × 10−3 mol% of catalyst 3Mn (Scheme 37). From the several oxime derivatives tested, the aromatic Scheme 37. Oxidation of Oximes by Molecular Oxygen Catalyzed by Metalloporphyrins

catalyst 56Fe (2 mol%), pressure of 0.1 MPa, in water at pH 7 and room temperature, leading to the corresponding lactones in quite high yields, proving to be an artificial biomimetic NAD(P)H oxidase, compatible with different types of preparative enzymatic oxidations. Ji157 evaluated the oxidation of sulfides to sulfoxides with dioxygen, catalyzed by cationic catalysts type 34 (Figure 6), using 1 mmol of thioanisole as model compound, the authors tested the effect of the metal inside the porphyrin cavity, with 0.07 mol% catalyst, 3 equiv of isobutyraldehyde as co-oxidant, O2 pressure of 0.1 MPa in toluene at 80 °C (Scheme 39). Catalyst 34Mn presented the best activity for the oxidation of sulfides, completely converting the thioanisole into the corresponding sulfoxide with 95% selectivity. The reaction scope was enlarged to several other thiol-compounds, using the same reaction conditions, always with high conversion rate and excellent selectivity. The electron donation at para-position of phenyl ring groups revealed to be more favorable to the conversion of sulfides, when compared with the electron withdrawal. In addition, the influence of steric effects could be observed, as the oxidation of diphenyl sulfide and isopropyl phenyl sulfide needed longer reaction times to achieve conversions of 82 and 89%, respectively. Moreover, sulfoxidation of the linear chain sulfide proceeded with high

oximes were the most prone to oxidation. Interestingly, substrates with electron-withdrawing groups at the orthoposition gave nitriles as products, while substrates bearing electron-donating groups still produced ketones. Groeger156 prepared water-soluble porphyrin-based catalysts 53-56 (Figure 10), which have been evaluated in the biomimetic oxidation of NAD(P)H to NAD(P)+ (Scheme 38). However, only complex 56Fe was able to promote oxidative transformation of the cofactor NAD(P)H in aqueous medium. Leaning on this results,156 complex 56Fe was used to promote the oxidation of D-glucose, D-mannose, and D-xylose (Scheme 38), in the presence of glucose dehydrogenase, 10801


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Figure 10. Homogeneous and heterogeneous metalloporphyrin catalysts for oxidation of miscellaneous substrates.

sulfonatophenyl)porphyrin 57Rh (Figure 10) and molecular oxygen as oxidant (Scheme 40). A series of aliphatic amines

Scheme 39. Oxidation of Sulfides to Sulfoxides with Dioxygen, Catalyzed by Cationic Metalloporphyrins Immobilized onto Montmorillonite

Scheme 40. Aerobic N-Dealkylation of Secondary Amines Catalyzed by Ruthenium Porphyrin

and aniline substrates were investigated, under the optimum conditions, at 100 °C for 6 h, using MeOH:H2O (9:1) as solvent. Substrate scope evaluation suggested that bulkier secondary amines gave higher yields than the primary amines. Inhibiting product coordination seemed to be crucial for improving reaction efficiency. Moreover, the authors introduced benzaldehyde in the reaction to selectively trap the resulting primary amine by immediate formation of corresponding imine. The authors concluded that the rapid hydrolysis of the iminium ions, in a protic solvent, as well as fast reoxidation of Rh(I) to Rh(III) species by molecular oxygen might be the key factors to promote more efficient oxidative N-dealkylation reactions. Hayashi159 reported the oxygenation of several cyclic disilanes, catalyzed by Co(III)Cl porphyrin complexes 3Co (Figure 4), 58Co, and 59Co (Figure 10). Five- and sixmembered cyclic disilanes were readily oxygenated, using 10 mol% of catalyst, [disilane] = 1.5 × 10−2 M in CHCl3 at 25 °C in air, providing the corresponding cyclic disiloxanes in quantitative yields (Scheme 41).

conversion and selectivity, as well as sulfide containing hydroxyl group, where no products from hydroxyl group oxidation were detected. Furthermore, the stability of the catalyst 34Mn was evaluated using several sequential aerobic oxidation reactions of thioanisole in the presence of isobutyraldehyde. The catalyst was recovered by centrifugation and filtration, washed with acetonitrile, and dried before being used in the subsequent run, without significant loss of activity and metalloporphyrin leaching, as checked by UV−vis spectra of the solution at the end of each reaction.157 Pereira and Calvete141 also described the use of the porphyrin immobilized onto magnetic nanoparticles 44Cu (Figure 7), to promote the catalytic oxidation of thiophenol with O2 without the presence of any additive, yielding diphenyl disulfide in 98%. The catalyst was recovery by magnetic separation and reused for three times. Fu158 reported the catalytic oxidative N-dealkylation of secondary amines catalyzed by Rh(III) meso-tetra(p10802


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lysts, especially using inorganic supports for more accessible reutilization protocols. The highest challenges will naturally remain increasing the catalyst’s activity and/or selectivity. Chemists ought to keep their efforts focused on finding solutions that avoid the use of highly pollutant co-oxidants and/or co-catalysts, emphasizing on the sole use of environmentally benign oxidant sources, such as molecular oxygen. Mimicking Nature, namely in the oxidative reactions promoted by the cytochrome P-450 enzyme, is still one of the big challenges for chemists in the next decade. Of the several achievements described in this Review, we can propose the following molecular design: (i) introduction of electronwithdrawing groups at the periphery of metalloporphyrins, preferably at meso-positions, and (ii) selection of the metal, according with the type of reaction, e.g., cobalt for the oxidation of alkanes and manganese(III) and/or iron(III) for the epoxidation of olefins in the presence of co-reductants or ideally, stable ruthenium porphyrins without co-reductant. However, to allow these systems to be translated to the industrial scale, it is necessary to unite the activity and selectivity of homogeneous catalysis with the reusability of heterogeneous catalysts. Hence, we consider that, to avoid catalyst leaching, it is essential to develop catalysts covalently linked to inorganic solid supports (to avoid support selfoxidation). Summing all up, we believe that the primary objective when designing/developing catalytic oxidation systems based on metalloporphyrins using O2 as oxidant must be a recycle/reuse principle, and heterogeneous systems are currently the only ones that offer a sustainable approach for development of immobilized oxidation catalysts onto solid supports.

Scheme 41. Oxygenation of Disilanes Catalyzed by Co(III) Cl Porphyrin Complexes

3. CONCLUSIONS AND PERSPECTIVES The discovery of cytochrome P-450’s structure and elucidation of its mechanism of action have driven the use of metalloporphyrins as biomimetic catalysts for the oxidation of organic molecules. At first, homogeneous systems presented the most amenable strategy for oxidizing a vast array of substrates; however, current environmental concerns and enhancement of catalyst stability have directed research in this field for the design, synthesis, and application of heterogeneous catalysts. The immobilization of metalloporphyrins proved to be a very important strategy to avoid degradation of the homogeneous catalysts and to promote the catalysts’ re-utilization. From the examples presented herein, we can generally conclude that the nature of the active oxidative species and the final product selectivity depend on the interaction of the oxygen donor with the metal precursor, the structure of the porphyrin ligand, and the metal used. In the past decade, several successful approaches have been developed to obtain active/selective catalysts for oxidation of organic compounds. We find that, using an environmentally benign oxidant source, such as molecular oxygen, the central metal Co(III) seems to be the most adequate choice for C−H activation, probably given its more pronounced ability to give electrons to molecular oxygen (higher reduction potential) than other commonly used metals, such as Mn(III) or Fe(III). We find also that co-reductants like aldehydes are normally required to promote the transformation of olefins to epoxides, and in this case Mn(III) porphyrins are the most promising catalysts. In this case, the use of Co(III) and Fe(III) porphyrins is less recommended due to the concomitant occurrence of an autooxidation pathway. This points out that the mechanism of C− H oxidation under basic conditions with Co(III) porphyrins may involve an auto-oxidation process, yielding preferentially the aldehyde, while the iron and manganese catalysts may preferentially involve the formation of the oxo-metal(IV) porphyrin cation radical, compound 1. Additionally, in most cases, the use of metalloporphyrins bearing electron-withdrawing or -donating groups is not absolutely determining for the activity/selectivity of the catalysts. Ultimately, the immobilization of metalloporphyrins may prove to be a very important strategy to avoid degradation of the catalysts and to promote the catalysts’ re-utilization. Recent literature provides many examples where the use of such heterogeneous catalytic systems is successfully applied, and we forecast that in the next decade studies on the oxidation reactions of many relevant substrates will focus on the development of heterogeneous metalloporphyrin-based cata-

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AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. *E-mail: [email protected]. ORCID

Mariette M. Pereira: 0000-0003-4958-7677 Lucas D. Dias: 0000-0003-2858-7539 Mário J. F. Calvete: 0000-0003-2094-4781 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS The Coimbra Chemistry Centre is supported by the Fundaçaõ para a Ciência e a Tecnologia (FCT; Portuguese Foundation for Science and Technology) through Projects PEst-OE/QUI/ UI0313/2014. We are grateful to PT2020 POCI-01-0145FEDER-027996 for funding. L.D.D. thanks CNPq - Brasil ́ (Conselho Nacional de Desenvolvimento Cientifico e Tecnológico) for Ph.D. grant 232620/2014-8/GDE. M.J.F.C. is grateful to FCT for postdoctoral grant SFRH/BPD/99698/ 2014.

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REFERENCES

(1) Garfinkel, D. Studies on Pig Liver Microsomes 0.1. Enzymic and Pigment Composition of Different Microsomal Fractions. Arch. Biochem. Biophys. 1958, 77, 493−509. (2) Klingenberg, M. Pigments of Rat Liver Microsomes. Arch. Biochem. Biophys. 1958, 75, 376−386. (3) Omura, T.; Sato, R. A New Cytochrome in Liver Microsomes. J. Biol. Chem. 1962, 237, 1375−1376.

10803


Review

ACS Catalysis (4) Omura, T.; Sato, R. Carbon Monoxide-Binding Pigment of Liver Microsomes. I. Evidence for Its Hemoprotein Nature. J. Biol. Chem. 1964, 239, 2370−2378. (5) Katagiri, M.; Ganguli, B. N.; Gunsalus, I. C. A Soluble Cytochrome P-450 Functional in Methylene Hydroxylation. J. Biol. Chem. 1968, 243, 3543−3546. (6) Microsomes and Drug Oxidations; Gillette, J. R., Conney, A. H., Cosmides, G. J., Eds.; Academic Press: New York, 1969. (7) Tang, S. C.; Koch, S.; Papaefthymiou, G. C.; Foner, S.; Frankel, R. B.; Ibers, J. A.; Holm, R. H. Axial Ligation Modes in Iron(Iii) Porphyrins - Models for Oxidized Reaction States of Cytochrome-P450 Enzymes and Molecular-Structure of Iron(Iii) Protoporphyrin Ix Dimethyl Ester Para-Nitrobenzenethiolate. J. Am. Chem. Soc. 1976, 98, 2414−2434. (8) The Porphyrins, Biochemistry-Part B, Vol. 7; Dolphin, D., Ed.; Academic Press: New York, 1978. (9) Tabushi, I.; Yazaki, A. P-450-Tpye Dioxygen Activation Using Hydrogen/Colloidal Platinum as an Effective Electron Donor. J. Am. Chem. Soc. 1981, 103, 7371−7373. (10) Cytochrome P450; Rückpaul, K., Rein, H., Eds.; AkademieVerlag: Berlin, 1984. (11) Tabushi, I.; Kodera, M.; Yokoyama, M. Kinetics and Mechanism of Reductive Dioxygen Activation Catalyzed by the P450 Model System - Iron Picket Fence as a Catalytic Center. J. Am. Chem. Soc. 1985, 107, 4466−4473. (12) Groves, J. T. Key Elements of the Chemistry of Cytochrome-P450 - the Oxygen Rebound Mechanism. J. Chem. Educ. 1985, 62, 928−931. (13) Poulos, T. L.; Finzel, B. C.; Gunsalus, I. C.; Wagner, G. C.; Kraut, J. The 2.6-a Crystal-Structure of Pseudomonas-Putida Cytochrome-P-450. J. Biol. Chem. 1985, 260, 6122−6130. (14) Cytochrome P450: Structure, Mechanism and Biochemistry, 1st ed.; Ortiz de Montellano, P. R., Ed.; Plenum Press: New York and London, 1986. (15) McMurry, T. J.; Groves, J. T. In Cytochrome P450: Structure, Mechanism and Biochemistry, 1st ed.; Ortiz de Montellano, P. R., Ed.; Plenum Press: New York and London, 1986; p 1. (16) Groves, J. T.; Watanabe, Y. Reactive Iron Porphyrin Derivatives Related to the Catalytic Cycles of Cytochrome-P-450 and Peroxidase - Studies of the Mechanism of Oxygen Activation. J. Am. Chem. Soc. 1988, 110, 8443−8452. (17) Mansuy, D.; Bartoli, J. F.; Battioni, P.; Lyon, D. K.; Finke, R. G. Highly Oxidation Resistant Inorganic-Porphyrin Analog Polyoxometalate Oxidation Catalysts. 2. Catalysis of Olefin Epoxidation and Aliphatic and Aromatic Hydroxylations Starting form Alpha-2P2W17O61(Mn+.Br)(N-11) (Mn+ = Mn3+, Fe3+, Co2+, Ni2+, Cu2+), Including Quantitative Comparisons to Metalloporphyrin Catalysts. J. Am. Chem. Soc. 1991, 113, 7222−7226. (18) Hoffmann, P.; Robert, A.; Meunier, B. Preparation and Catalytic Activities of the Manganese and Iron Derivatives of BR8TMP and CL12TMP, 2 Robust Porphyrin Ligands Obtained by Halogenation of Tetramesitylporphyrin. Bull. Soc. Chim. Fr. 1992, 129, 85−97. (19) Collman, J. P.; Zhang, X. M.; Lee, V. J.; Uffelman, E. S.; Brauman, J. I. Regioselective and Enantioselective Epoxidation Catalyzed by Metalloporphyrins. Science 1993, 261, 1404−1411. (20) Arasasingham, R. D.; He, G. X.; Bruice, T. C. Mechanism of Manganese Porphyrin-Catalyzed Oxidation of Alkenes - Role of Manganese(IV) Oxo Species. J. Am. Chem. Soc. 1993, 115, 7985− 7991. (21) Parton, R. F.; Vankelecom, I. F. J.; Casselman, M. J. A.; Bezoukhanova, C. P.; Uytterhoeven, J. B.; Jacobs, P. A. An efficient Mimic of Cytochrome P-450 from a Zeolite Encaged Iron Complex in a Polymer Membrane. Nature 1994, 370, 541−544. (22) Groves, J. T.; Gross, Z.; Stern, M. K. Preparation and Reactivity of Oxoiron(IV) Porphyrins. Inorg. Chem. 1994, 33, 5065−5072. (23) Cytochrome P450: Structure, Mechanism and Biochemistry, 2nd ed.; Ortiz de Montellano, P. R., Ed.; Plenum Press: New York and London, 1995.

(24) Nam, W. W.; Kim, H. J.; Kim, S. H.; Ho, R. Y. N.; Valentine, J. S. Metal Complex-Catalyzed Epoxidation of Olefins by Dioxygen with Co-Oxidation of Aldehydes. A Mechanistic Study. Inorg. Chem. 1996, 35, 1045−1049. (25) Neumann, R.; Dahan, M. A Ruthenium-Substituted Polyoxometalate as an Inorganic Dioxygenase for Activation of Molecular Oxygen. Nature 1997, 388, 353−355. (26) Shaik, S.; Filatov, M.; Schroder, D.; Schwarz, H. Electronic Structure Makes a Difference: Cytochrome P-450 Mediated Hydroxylations of Hydrocarbons as a Two-State Reactivity Paradigm. Chem. - Eur. J. 1998, 4, 193−199. (27) Collman, J. P.; Chien, A. S.; Eberspacher, T. A.; Brauman, J. I. Multiple Active Oxidants in Cytochrome P-450 Model Oxidations. J. Am. Chem. Soc. 2000, 122, 11098−11100. (28) Nam, W.; Lim, M. H.; Moon, S. K.; Kim, C. Participation of Two Distinct Hydroxylating Intermediates in Iron(III) Porphyrin Complex-Catalyzed Hydroxylation of Alkanes. J. Am. Chem. Soc. 2000, 122, 10805−10809. (29) Mansuy, D.; Battioni, P. In The Porphyrin Handbook; Kadish, K., Guilard, R., Smith, K. M., Eds.; Academic Press: New York, 2000; Vol. 4, pp 1−16. (30) Williams, P. A.; Cosme, J.; Sridhar, V.; Johnson, E. F.; McRee, D. E. Mammalian Microsomal Cytochrome P450 Monooxygenase: Structural Adaptations for Membrane Binding and Functional Diversity. Mol. Cell 2000, 5, 121−131. (31) Yang, J.; Gabriele, B.; Belvedere, S.; Huang, Y.; Breslow, R. Catalytic Oxidations of Steroid Substrates by Artificial Cytochrome P450 Enzymes. J. Org. Chem. 2002, 67, 5057−5067. (32) Han, J. H.; Yoo, S. K.; Seo, J. S.; Hong, S. J.; Kim, S. K.; Kim, C. Biomimetic Alcohol Oxidations by an Iron(III) Porphyrin Complex: Relevance to Cytochrome P-450 Catalytic Oxidation and Involvement of the Two-State Radical Rebound Mechanism. Dalton Trans. 2005, 402−406. (33) Rothemund, P. Formation of Porphyrins From Pyrrole and Aldehydes. J. Am. Chem. Soc. 1935, 57, 2010−2011. (34) Rothemund, P. A New Porphyrin Synthesis. The Synthesis of Porphin. J. Am. Chem. Soc. 1936, 58, 625−627. (35) Adler, A. D.; Shergalis, W.; Longo, F. R. Mechanistic Investigations of Porphyrin Syntheses.I. Preliminary Studies on MsTetraphenylporphin. J. Am. Chem. Soc. 1964, 86, 3145−3149. (36) Adler, A. D.; Longo, F. R.; Finarelli, J. D.; Goldmacher, J.; Assour, J.; Korsakoff, L. A Simplified Synthesis for MesoTetraphenylporphin. J. Org. Chem. 1967, 32, 476. (37) Longo, F. R.; Finarelli, M. G.; Kim, J. B. Synthesis and Some Physical Properties of MS-Tetra(pentafluorophenyl − Porphin and MS-Tetra(pentachlorophenyl) Porphin. J. Heterocycl. Chem. 1969, 6, 927. (38) Gonsalves, A. M. D. R.; Pereira, M. M. A New Look into the Rothemund Meso-Tetraalkyl and Tetraarylporphyrin Synthesis. J. Heterocycl. Chem. 1985, 22, 931−933. (39) Gonsalves, A. M. A. R.; Varejao, J. M. T. B.; Pereira, M. M. Some New Aspects Related to the Synthesis of Mesosubstituted Porphyrins. J. Heterocycl. Chem. 1991, 28, 635−640. (40) Gonsalves, A. M. D. R.; Johnstone, R. A. W.; Pereira, M. M.; Shaw, J.; Sobral, A. J. F. D. Metal-Assisted Reactions 0.22. Synthesis of Perhalogenated Porphyrins and Their Use as Oxidation Catalysts. Tetrahedron Lett. 1991, 32, 1355−1358. (41) Lindsey, J. S.; Hsu, H. C.; Schreiman, I. C. Synthesis of Tetraphenylporphyrins Under Very Mild Conditions. Tetrahedron Lett. 1986, 27, 4969−4970. (42) Lindsey, J. S.; Schreiman, I. C.; Hsu, H. C.; Kearney, P. C.; Marguerettaz, A. M. Rothemund and Adler-Longo Reactions Revisited - Synthesis of Tetraphenylporphyrins under Equilibrium Conditions. J. Org. Chem. 1987, 52, 827−836. (43) Wagner, R. W.; Lawrence, D. S.; Lindsey, J. S. An Improved Synthesis of tetramesitylporphyrin. Tetrahedron Lett. 1987, 28, 3069− 3070. 10804


Review

ACS Catalysis (44) Lindsey, J. S.; Wagner, R. W. Investigation of the Synthesis of ortho-Substituted Tetraphenylporphyrins. J. Org. Chem. 1989, 54, 828−836. (45) Lindsey, J. S. Synthetic Routes to meso-Patterned Porphyrins. Acc. Chem. Res. 2010, 43, 300−311. (46) Rao, P. D.; Dhanalekshmi, S.; Littler, B. J.; Lindsey, J. S. Rational Syntheses of Porphyrins Bearing up to Four Different meso Substituents. J. Org. Chem. 2000, 65, 7323−7344. (47) Geier, G. R.; Lindsey, J. S. Effects of Diverse Acid Catalysts on the Reaction Course in the Two-Step One-Flask Synthesis of mesoTetraphenylporphyrin. J. Porphyrins Phthalocyanines 2002, 6, 159− 185. (48) Tomizaki, K.; Loewe, R. S.; Kirmaier, C.; Schwartz, J. K.; Retsek, J. L.; Bocian, D. F.; Holten, D.; Lindsey, J. S. Synthesis and Photophysical Properties of Light-Harvesting Arrays Comprised of a Porphyrin Bearing Multiple Perylene-Monoimide Accessory Pigments. J. Org. Chem. 2002, 67, 6519−6534. (49) Geier, G. R.; Lindsey, J. S. Effects of Aldehyde or Dipyrromethane Substituents on the Reaction Course Leading to meso-Substituted Porphyrins. Tetrahedron 2004, 60, 11435−11444. (50) Thamyongkit, P.; Speckbacher, M.; Diers, J. R.; Kee, H. L.; Kirmaier, C.; Holten, D.; Bocian, D. F.; Lindsey, J. S. Swallowtail Porphyrins: Synthesis, Characterization and Incorporation Into Porphyrin Dyads. J. Org. Chem. 2004, 69, 3700−3710. (51) Bhaumik, J.; Yao, Z.; Borbas, K. E.; Taniguchi, M.; Lindsey, J. S. Masked Imidazolyl-Dipyrromethanes in the Synthesis of ImidazoleSubstituted Porphyrins. J. Org. Chem. 2006, 71, 8807−8817. (52) Thamyongkit, P.; Bhise, A. D.; Taniguchi, M.; Lindsey, J. S. Alkylthio Unit as an Alpha-Pyrrole Protecting Group for Use in Dipyrromethane Synthesis. J. Org. Chem. 2006, 71, 903−910. (53) Kulikov, O. V.; Schmidt, I.; Muresan, A. Z.; Lee, M. A. P.; Bocian, D. F.; Lindsey, J. S. Synthesis of Porphyrins for Metal Deposition Studies in Molecular Information Storage Applications. J. Porphyrins Phthalocyanines 2007, 11, 699−712. (54) Lahaye, D.; Muthukumaran, K.; Hung, C. H.; Gryko, D.; Reboucas, J. S.; Spasojevic, I.; Batinic-Haberle, I.; Lindsey, J. S. Design and Synthesis of Manganese Porphyrins with Tailored Lipophilicity: Investigation of Redox Properties and Superoxide Dismutase Activity. Bioorg. Med. Chem. 2007, 15, 7066−7086. (55) Muresan, A. Z.; Thamyongkit, P.; Diers, J. R.; Holten, D.; Lindsey, J. S.; Bocian, D. F. Regiospecifically alpha-C-13-Labeled Porphyrins for Studies of Ground-State Hole Transfer in Multiporphyrin Arrays. J. Org. Chem. 2008, 73, 6947−6959. (56) Taniguchi, M.; Lindsey, J. S. Synthesis of Oligo(p-Phenylene)Linked Dyads Containing Free Base, Zinc(II) or Thallium(III) Porphyrins for Studies in Artificial Photosynthesis. Tetrahedron 2010, 66, 5549−5565. (57) Lindsey, J. S. De Novo Synthesis of Gem-Dialkyl Chlorophyll Analogues for Probing and Emulating Our Green World. Chem. Rev. 2015, 115, 6534−6620. (58) Taniguchi, M.; Lindsey, J. S. Synthetic Chlorins, Possible Surrogates for Chlorophylls, Prepared by Derivatization of Porphyrins. Chem. Rev. 2017, 117, 344−535. (59) Henriques, C. A.; Goncalves, N. P. F.; Abreu, A. R.; Calvete, M. J. F.; Pereira, M. M. Unsymmetrical Porphyrins: the Role of mesoSubstituents on Their Physical Properties. J. Porphyrins Phthalocyanines 2012, 16, 290−296. (60) Silva, M.; Fernandes, A.; Bebiano, S. S.; Calvete, M. J. F.; Ribeiro, M. F.; Burrows, H. D.; Pereira, M. M. Size and Ability Do Matter! Influence of Acidity and Pore size on the Synthesis of Hindered Halogenated meso-Phenyl Porphyrins Catalysed by Porous Solid Oxides. Chem. Commun. 2014, 50, 6571−6573. (61) Calvete, M. J. F.; Dias, L. D.; Henriques, C. A.; Pinto, S. M. A.; Carrilho, R. M. B.; Pereira, M. M. A Cost-Efficient Method for Unsymmetrical Meso-Aryl Porphyrin Synthesis Using NaY Zeolite as an Inorganic Acid Catalyst. Molecules 2017, 22, 741. (62) Shinoda, T.; Izumi, Y.; Onaka, M. FSM-16 - A Recyclable Mesoporous Acid Promoter for Meso-Tetraarylporphyrin Synthesis. J. Chem. Soc., Chem. Commun. 1995, 1801−1802.

(63) Drain, C. M.; Gong, X. C. Synthesis of meso substituted porphyrins in air without solvents or catalysts. Chem. Commun. 1997, 2117−2118. (64) Algarra, F.; Esteves, M. A.; Fornes, V.; Garcia, H.; Primo, J. Condensation of pyrrole with aldehydes in the presence of Y zeolites and mesoporous MCM-41 aluminosilicate: on the encapsulation of porphyrin precursors. New J. Chem. 1998, 22, 333−338. (65) Kitaoka, S.; Nobuoka, K.; Ishikawa, Y. The first utilization of acidic ionic liquid for preparation of tetraarylporphyrins. Chem. Commun. 2004, 1902−1903. (66) Henriques, C. A.; Pinto, S. M. A.; Aquino, G. L. B.; Pineiro, M.; Calvete, M. J. F.; Pereira, M. M. Ecofriendly Porphyrin Synthesis by using Water under Microwave Irradiation. ChemSusChem 2014, 7, 2821−2824. (67) Henriques, C. A.; Pinto, S. M. A.; Pineiro, M.; Canotilho, J.; Eusebio, M. E. S.; Pereira, M. M.; Calvete, M. J. F. Solventless Metallation of Low Melting Porphyrins Synthesized by the Water/ Microwave method. RSC Adv. 2015, 5, 64902−64910. (68) Pinto, S. M. A.; Henriques, C. A.; Tome, V. A.; Vinagreiro, C. S.; Calvete, M. J. F.; Dabrowski, J. M.; Pineiro, M.; Arnaut, L. G.; Pereira, M. M. Synthesis of meso-Substituted Porphyrins Using Sustainable Chemical Processes. J. Porphyrins Phthalocyanines 2016, 20, 45−60. (69) Petit, A.; Loupy, A.; Maillard, P.; Momenteau, M. Microwave Irradiation in Dry Media - A New and Easy Method for Synthesis of Tetrapyrrolic Compounds. Synth. Commun. 1992, 22, 1137−1142. (70) Nascimento, B. F. O.; Pineiro, M.; Gonsalves, A.; Silva, M. R.; Beja, A. M.; Paixao, J. A. Microwave-assisted synthesis of porphyrins and metalloporphyrins: a rapid and efficient synthetic method. J. Porphyrins Phthalocyanines 2007, 11, 77−84. (71) Lucas, R.; Vergnaud, J.; Teste, K.; Zerrouki, R.; Sol, V.; Krausz, P. A facile and rapid iodine-catalyzed meso-tetraphenylporphyrin synthesis using microwave activation. Tetrahedron Lett. 2008, 49, 5537−5539. (72) Momo, P. B.; Bellete, B. S.; Brocksom, T. J.; de Souza, R.; de Oliveira, K. T. Exploiting novel process windows for the synthesis of meso-substituted porphyrins under continuous flow conditions. RSC Adv. 2015, 5, 84350−84355. (73) Huang, X. Y.; Groves, J. T. Oxygen Activation and Radical Transformations in Heme Proteins and Metalloporphyrins. Chem. Rev. 2018, 118, 2491−2553. (74) Groves, J. T.; Nemo, T. E.; Myers, R. S. Hydroxylation and Epoxidation Catalyzed by Iron Porphyrin Complexes - OxygenTransfer from Iodosylbenzene. J. Am. Chem. Soc. 1979, 101, 1032− 1033. (75) Groves, J. T.; Haushalter, R. C.; Nakamura, M.; Nemo, T. E.; Evans, B. J. High-Valent Iron-Porphyrin Complexes Related to Peroxidase and Cytochrome P-450. J. Am. Chem. Soc. 1981, 103, 2884−2886. (76) Groves, J. T.; Myers, R. S. Catalytic Asymetric Epoxidations with Chiral Iron porphyrins. J. Am. Chem. Soc. 1983, 105, 5791−5796. (77) Groves, J. T.; Nemo, T. E. Epoxidation Reactions Catalyzed by Iron Porphyrins - Oxygen-Transfer from Iodosylbenzene. J. Am. Chem. Soc. 1983, 105, 5786−5791. (78) Groves, J. T.; Nemo, T. E. Aliphatic Hydroxylation Catalyzed by Iron Porphyrin Complexes. J. Am. Chem. Soc. 1983, 105, 6243− 6248. (79) Gonsalves, A.; Pereira, M. M. State of the art in the development of biomimetic oxidation catalysts. J. Mol. Catal. A: Chem. 1996, 113, 209−221. (80) Gonsalves, A.; Johnstone, R. A. W.; Pereira, M. M.; Shaw, J. Metal-Assisted Reactions. 21. Epoxidation of Alkenes Catalyzed by Manganese-Porphyrins - The Effects of Various Oxidatively-Stable Ligands and Bases. J. Chem. Soc., Perkin Trans. 1 1991, 1, 645−649. (81) Groves, J. T.; Quinn, R. Aerobic Epoxidation of Olefins with Ruthenium Porphyrin Catalysts. J. Am. Chem. Soc. 1985, 107, 5790− 5792. 10805


Review

ACS Catalysis (82) Wentzel, B. B.; Alsters, P. L.; Feiters, M. C.; Nolte, R. J. M. Mechanistic Studies on the Mukaiyama Epoxidation. J. Org. Chem. 2004, 69, 3453−3464. (83) Ji, H.-B.; Zhou, X.-T. Biomimetic Epoxidation of Olefins Catalyzed by Metalloporphyrins with Molecular Oxygen. Intech Open 2011, 14046. (84) Zucca, P.; Rescigno, A.; Rinaldi, A. C.; Sanjust, E. Biomimetic metalloporphines and metalloporphyrins as potential tools for delignification: Molecular mechanisms and application perspectives. J. Mol. Catal. A: Chem. 2014, 388, 2−34. (85) Baglia, R. A.; Zaragoza, J. P. T.; Goldberg, D. P. Biomimetic Reactivity of Oxygen-Derived Manganese and Iron Porphyrinoid Complexes. Chem. Rev. 2017, 117, 13320−13352. (86) Rebelo, S. L. H.; Pereira, M. M.; Simoes, M. M. Q.; Neves, M.; Cavaleiro, J. A. S. Mechanistic studies on metalloporphyrin epoxidation reactions with hydrogen peroxide: evidence for two active oxidative species. J. Catal. 2005, 234, 76−87. (87) Hlavica, P. Models and mechanisms of O-O bond activation by cytochrome P450 - A critical assessment of the potential role of multiple active intermediates in oxidative catalysis. Eur. J. Biochem. 2004, 271, 4335−4360. (88) Cytochrome P450: Structure, Mechanism and Biochemistry, 3rd ed.; Ortiz de Montellano, P. R., Ed.; Kluwer Academic/Plenum Publisher: New York, 2005. (89) Ortiz de Montellano, P. R.; De Voss, J. J. In Cytochrome P450: Structure, Mechanism and Biochemistry, 3rd ed.; Ortiz de Montellano, P. R., Ed.; Kluwer Academic/Plenum Publisher: New York, 2005; pp 183−245. (90) Mansuy, D. A Brief History of the Contribution of Metalloporphyrin Models to Cytochrome P450 Chemistry and Oxidation Catalysis. C. R. Chim. 2007, 10, 392−413. (91) Che, C. M.; Huang, J. S. Metalloporphyrin-based oxidation systems: from biomimetic reactions to application in organic synthesis. Chem. Commun. 2009, 3996−4015. (92) Murphy, B. E.; Krasnikov, S. A.; Sergeeva, N. N.; Cafolla, A. A.; Preobrajenski, A. B.; Chaika, A. N.; Lubben, O.; Shvets, I. V. Homolytic Cleavage of Molecular Oxygen by Manganese Porphyrins Supported on Ag(111). ACS Nano 2014, 8, 5190−5198. (93) Arcon, J. P.; Rosi, P.; Petruk, A. A.; Marti, M. A.; Estrin, D. A. Molecular Mechanism of Myoglobin Autoxidation: Insights from Computer Simulations. J. Phys. Chem. B 2015, 119, 1802−1813. (94) Burns, E.; Huang, T.; Weare, W. W.; Bartolotti, L.; Wang, X. Y.; Yao, J.; Li, H. R.; Franzen, S. Aerobic Oxidation of beta-Isophorone by Tetraphenylporphyrin Catalysts in Pyridine Solution. J. Mol. Catal. A: Chem. 2015, 410, 110−120. (95) Li, H.; She, Y. B.; Fu, H. Y.; Cao, M. J.; Wang, J.; Wang, T. Synergistic Effect of Co-Reactant Promotes One-Step Oxidation of Cyclohexane into Adipic Acid Catalyzed by Manganese Porphyrins. Can. J. Chem. 2015, 93, 696−701. (96) Wang, B. J.; Li, C. S.; Dubey, K. D.; Shaik, S. Quantum Mechanical/Molecular Mechanical Calculated Reactivity Networks Reveal How Cytochrome P450cam and Its T252A Mutant Select Their Oxidation Pathways. J. Am. Chem. Soc. 2015, 137, 7379−7390. (97) Jiang, J.; Luo, R. C.; Zhou, X. T.; Wang, F. F.; Ji, H. B. Metalloporphyrin-Mediated Aerobic Oxidation of Hydrocarbons in Cumene: Co-Substrate Specificity and Mechanistic Consideration. Molecular Catalysis 2017, 440, 36−42. (98) Kepp, K. P. Heme: From Quantum Spin Crossover to Oxygen Manager of Life. Coord. Chem. Rev. 2017, 344, 363−374. (99) Gallagher, A. T.; Lee, J. Y.; Kathiresan, V.; Anderson, J. S.; Hoffman, B. M.; Harris, T. D. A Structurally Characterized Peroxomanganese(IV) Porphyrin from Reversible O-2 Binding Within a Metal-Organic Framework. Chemical Science 2018, 9, 1596−1603. (100) Schwizer, F.; Okamoto, Y.; Heinisch, T.; Gu, Y. F.; Pellizzoni, M. M.; Lebrun, V.; Reuter, R.; Kohler, V.; Lewis, J. C.; Ward, T. R. Artificial Metalloenzymes: Reaction Scope and Optimization Strategies. Chem. Rev. 2018, 118, 142−231.

(101) Yu, F. T.; Cangelosi, V. M.; Zastrow, M. L.; Tegoni, M.; Plegaria, J. S.; Tebo, A. G.; Mocny, C. S.; Ruckthong, L.; Qayyum, H.; Pecoraro, V. L. Protein Design: Toward Functional Metalloenzymes. Chem. Rev. 2014, 114, 3495−3578. (102) Hayashi, T.; Hisaeda, Y. New functionalization of myoglobin by chemical modification of heme-propionates. Acc. Chem. Res. 2002, 35, 35−43. (103) Zhao, M.; Wu, C. D. Biomimetic Activation of Molecular Oxygen with a Combined Metalloporphyrinic Framework and Cocatalyst Platform. ChemCatChem 2017, 9, 1192−1196. (104) She, Y. B.; Wang, W. J.; Li, G. J. Oxidation of p/o-Cresols to p/o-Hydroxybenzaldehydes Catalyzed by Metalloporphyrins with Molecular Oxygen. Chin. J. Chem. Eng. 2012, 20, 262−266. (105) Kadish, K. M.; Bottomley, L. A.; Kelly, S.; Schaeper, D.; Shiue, L. R. On the Tuning of metalloporphyrin Redox Potentials. Bioelectrochem. Bioenerg. 1981, 8, 213−222. (106) Jiang, J. A.; Chen, C.; Guo, Y.; Liao, D. H.; Pan, X. D.; Ji, Y. F. A highly efficient approach to vanillin starting from 4-cresol. Green Chem. 2014, 16, 2807−2814. (107) Guo, C. C.; Liu, Q.; Wang, X. T.; Hu, H. Y. Selective liquid phase oxidation of toluene with air. Appl. Catal., A 2005, 282, 55−59. (108) Luo, W. P.; Liu, D. W.; Sun, J.; Deng, W.; Sheng, W. B.; Liu, Q.; Guo, C. C. Effects of Oxygen Transfer Limitation and Kinetic Control on Biomimetic Catalytic Oxidation of Toluene. Chin. J. Chem. Eng. 2014, 22, 509−515. (109) Zhou, W. Y.; Sun, C. G.; Xu, S. C.; Hu, B. C. MetalloDeuteroporphyrin as a Novel Catalyst for p-Xylene Oxidation Using Molecular Oxygen. Inorg. Chim. Acta 2012, 382, 167−170. (110) Li, Y. J.; Sun, B. S.; Zhou, Y. R.; Yang, W. J. Novel Conjugated Nanoporous Alkynyl Metalloporphyrin Framework as Effective Catalyst for Oxidation of Toluene with Molecular Oxygen. Appl. Organomet. Chem. 2017, 31, 3578−3584. (111) Li, Y. J.; Liu, C. R.; Yang, W. J. Synthesis of Porous Polymeric Metalloporphyrins for Highly Efficient Oxidation of Cyclohexane in Heterogeneous Systems. New J. Chem. 2017, 41, 8214−8221. (112) Wang, R. X.; Jiao, W. Z.; Gao, B. J. Efficient Biomimetic Aerobic Oxidation of Phenylethane Catalyzed by P(4VP-co-St)/ SiO2-Supported Metalloporphyrins. Appl. Surf. Sci. 2009, 255, 7766− 7772. (113) Wang, R. X.; Zhu, H. L.; Gao, B. J. The Catalytic Activity of Poly(N-vinylimidazole)/SiO2-Supported Metalloporphyrins in Ethyl Benzene Oxidation. React. Kinet., Mech. Catal. 2011, 103, 431−441. (114) Huang, G.; Yuan, R. X.; Peng, Y.; Chen, X. F.; Zhao, S. K.; Wei, S. J.; Guo, W. X.; Chen, X. Oxygen Oxidation of Ethylbenzene Over Manganese Porphyrin is Promoted by the Axial Nitrogen Coordination in Powdered Chitosan. RSC Adv. 2016, 6, 48571− 48579. (115) Wang, P.; She, Y. B.; Fu, H. Y.; Zhao, W. B.; Wang, M. Oxidation of Alkylaromatics to Aromatic Ketones Catalyzed by Metalloporphyrins Under the Special Temperature Control Method. Can. J. Chem. 2014, 92, 1059−1065. (116) Tabor, E.; Poltowicz, J.; Pamin, K.; Basag, S.; Kubiak, W. Influence of Substituents in meso-Aryl Groups of Iron mu-Oxo Porphyrins on Their Catalytic Activity in the Oxidation of Cycloalkanes. Polyhedron 2016, 119, 342−349. (117) Guo, C. C.; Liu, X. Q.; Liu, Q.; Liu, Y.; Chu, M. F.; Lin, W. Y. First Industrial-Scale Biomimetic Oxidation of Hydrocarbon with Air over Metalloporphyrins as Cytochrome P-450 Monooxygenase Model and its Mechanistic Studies. J. Porphyrins Phthalocyanines 2009, 13, 1250−1254. (118) Hu, B. Y.; Yuan, Y. J.; Xiao, J.; Guo, C. C.; Liu, Q.; Tan, Z.; Li, Q. H. Rational Oxidation of Cyclohexane to Cyclohexanol, Cyclohexanone and Adipic Acid with Air over Metalloporphyrin and Cobalt Salt. J. Porphyrins Phthalocyanines 2008, 12, 27−34. (119) Hu, B. C.; Zhou, W. Y.; Ma, D. S.; Liu, Z. L. MetalloDeuteroporphyrins as Catalysts for the Oxidation of Cyclohexane with Air in the Absence of Additives and Solvents. Catal. Commun. 2008, 10, 83−85. 10806


Review

ACS Catalysis (120) Sun, C. G.; Hu, B. C.; Zhou, W. Y.; Xu, S. C.; Liu, Z. L. Synthesis of Disulfide-Derivatised Metallodeuteroporphyrins as Novel Catalysts to Imitate Cytochrome P-450 in the Selective Oxidation of Cyclohexane. J. Chem. Res. 2011, 35, 681−685. (121) Fu, B.; Yu, H. C.; Huang, J. W.; Zhao, P.; Ji, L. N. Synthesis and Catalytic Activities in Cyclohexane Hydroxylation of Metalloporphyrins Supported on Styrene-Methylacrylic Acid Copolymer Microspheres. Transition Met. Chem. 2008, 33, 803−807. (122) Fu, B.; Yu, H. C.; Huang, J. W.; Zhao, P.; Liu, J.; Ji, L. N. Mn(III) Porphyrins Immobilized on Magnetic Polymer Nanospheres as Biomimetic Catalysts Hydroxylating Cyclohexane with Molecular Oxygen. J. Mol. Catal. A: Chem. 2009, 298, 74−80. (123) Cai, J. H.; Huang, J. W.; Yu, H. C.; Ji, L. N. Manganese Porphyrins Immobilized on Silica Microspheres as Biomimetic Catalysts Hydroxylating Cyclohexane with Molecular Oxygen. J. SolGel Sci. Technol. 2011, 58, 698−704. (124) Huang, G.; Mo, L. Q.; Cai, J. L.; Cao, X.; Peng, Y.; Guo, Y. A.; Wei, S. J. Environmentally Friendly and Efficient Catalysis of Cyclohexane Oxidation by Iron meso-Tetrakis(pentafluorophenyl)porphyrin Immobilized on Zinc Oxide. Appl. Catal., B 2015, 162, 364−371. (125) Jiang, Y. X.; Su, T. M.; Qin, Z. Z.; Huang, G. A Zinc SulfideSupported Iron Tetrakis (4-Carboxyl Phenyl) Porphyrin Catalyst for Aerobic Oxidation of Cyclohexane. RSC Adv. 2015, 5, 24788−24794. (126) Huang, G.; Wang, W. L.; Ning, X. X.; Liu, Y.; Zhao, S. K.; Guo, Y. A.; Wei, S. J.; Zhou, H. Interesting Green Catalysis of Cyclohexane Oxidation over Metal Tetrakis(4-carboxyphenyl)porphyrins Promoted by Zinc Sulfide. Ind. Eng. Chem. Res. 2016, 55, 2959−2969. (127) Gao, B. J.; Qiao, Z. W.; Shi, N. Preparation of Heterogeneous Cationic Metalloporphyrin/Heteropolyanion Composite Catalysts and their High Catalytic Activity in Hydroxylation of Cyclohexane with Molecular Oxygen. J. Inclusion Phenom. Macrocyclic Chem. 2014, 79, 247−258. (128) Xu, S. C.; Zhao, Z. D.; Bi, L. W.; Chen, Y. X.; Li, D. M.; Wang, J.; Gu, Y.; Lu, Y. J. Selective Aerobic Hydroxylation of p-Menthane to Dihydroterpineols Catalyzed by Metalloporphyrins in Solvent and Additive Free System. Catal. Commun. 2015, 59, 26−29. (129) Zhu, S. L.; Xu, X.; Ou, S.; Zhao, M.; He, W. L.; Wu, C. D. Assembly of a Metalloporphyrin-Polyoxometalate Hybrid Material for Highly Efficient Activation of Molecular Oxygen. Inorg. Chem. 2016, 55, 7295−7300. (130) Brown, J. W.; Nguyen, Q. T.; Otto, T.; Jarenwattananon, N. N.; Gloggler, S.; Bouchard, L. S. Epoxidation of Alkenes with Molecular Oxygen Catalyzed by a Manganese Porphyrin-Based MetalOrganic Framework. Catal. Commun. 2015, 59, 50−54. (131) Beyzavi, M. H.; Vermeulen, N. A.; Howarth, A. J.; Tussupbayev, S.; League, A. B.; Schweitzer, N. M.; Gallagher, J. R.; Platero-Prats, A. E.; Hafezi, N.; Sarjeant, A. A.; Miller, J. T.; Chapman, K. W.; Stoddart, J. F.; Cramer, C. J.; Hupp, J. T.; Farha, O. K. A Hafnium-Based Metal-Organic Framework as a Nature-Inspired Tandem Reaction Catalyst. J. Am. Chem. Soc. 2015, 137, 13624− 13631. (132) Zhou, X. T.; Ji, H. B. Biomimetic kinetics and mechanism of cyclohexene epoxidation catalyzed by metalloporphyrins. Chem. Eng. J. 2010, 156, 411−417. (133) Li, Y.; Zhou, X. T.; Ji, H. B. Cocatalytic Effect of Cobalt Acetate on Aerobic Cyclohexene Oxidation Catalyzed by Manganese Porphyrin. Catal. Commun. 2012, 27, 169−173. (134) Li, Y.; Zhou, X. T.; Chen, S. Y.; Luo, R. C.; Jiang, J.; Liang, Z. X.; Ji, H. B. Direct Aerobic Liquid Phase Epoxidation of Propylene Catalyzed by Mn(III) Porphyrin under Mild Conditions: Evidence for the Existence of Both Peroxide and Mn(IV)-oxo Species From in situ Characterizations. RSC Adv. 2015, 5, 30014−30020. (135) Zhou, X. T.; Ji, H. B. Manganese Porphyrin Immobilized on Montmorillonite: a Highly Efficient and Reusable Catalyst for the Aerobic Epoxidation of Olefins Under Ambient Conditions. J. Porphyrins Phthalocyanines 2012, 16, 1032−1039.

(136) Rayati, S.; Nejabat, F. The Catalytic Efficiency of FePorphyrins Supported on Multi-Walled Carbon Nanotubes in the Oxidation of Olefins and Sulfides with Molecular Oxygen. New J. Chem. 2017, 41, 7987−7991. (137) Zhao, M.; Wu, C. D. Synthesis and Post-Metalation of a Covalent-Porphyrinic Framework for Highly Efficient Aerobic Epoxidation of Olefins. Catal. Commun. 2017, 99, 146−149. (138) Farokhi, A.; Hosseini-Monfared, H. A Recyclable MnPorphyrin Catalyst for Enantioselective Epoxidation of Unfunctionalized Olefins using Molecular Oxygen. New J. Chem. 2016, 40, 5032− 5043. (139) Berijani, K.; Hosseini-Monfared, H. Aerobic Enantioselective Epoxidation of Olefins Mediated by an Easy-to-Prepare Recyclable Manganese-Porphyrin. Mol. Catal. 2017, 433, 136−144. (140) Dias, L. D.; Carrilho, R. M. B.; Henriques, C. A.; Piccirillo, G.; Fernandes, A.; Rossi, L. M.; Filipa Ribeiro, M.; Calvete, M. J. F.; Pereira, M. M. A Recyclable Hybrid Manganese(III) Porphyrin Magnetic Catalyst for Selective Olefin Epoxidation using Molecular Oxygen. J. Porphyrins Phthalocyanines 2018, 22, 331−341. (141) Henriques, C. A.; Fernandes, A.; Rossi, L. M.; Ribeiro, M. F.; Calvete, M. J. F.; Pereira, M. M. Biologically Inspired and Magnetically Recoverable Copper Porphyrinic Catalysts: A Greener Approach for Oxidation of Hydrocarbons with Molecular Oxygen. Adv. Funct. Mater. 2016, 26, 3359−3368. (142) Smeureanu, G.; Aggarwal, A.; Soll, C. E.; Arijeloye, J.; Malave, E.; Drain, C. M. Enhanced Catalytic Activity and Unexpected Products from the Oxidation of Cyclohexene by Organic Nanoparticles of 5,10,15,20-Tetrakis-(2,3,4,5,6-pentafluorophenyl)porphyrinatoiron(III) in Water by Using O-2. Chem. - Eur. J. 2009, 15, 12133−12140. (143) Aggarwal, A.; Singh, S.; Drain, C. M. Nanoaggregates of Mn(III) Tetraperfluorophenylporphyrin: A Greener Approach for Allylic Oxidation of Olefins. J. Porphyrins Phthalocyanines 2011, 15, 1258−1264. (144) Aggarwal, A.; Singh, S.; Samson, J.; Drain, C. M. Adaptive Organic Nanoparticles of a Teflon-Coated Iron (III) Porphyrin Catalytically Activate Dioxygen for Cyclohexene Oxidation. Macromol. Rapid Commun. 2012, 33, 1220−1226. (145) Zhou, X. T.; Ji, H. B. Biomimetic kinetics and mechanism of cyclohexene epoxidation catalyzed by metalloporphyrins. Chem. Eng. J. 2010, 156, 411−417. (146) Berner, S.; Biela, S.; Ledung, G.; Gogoll, A.; Backvall, J. E.; Puglia, C.; Oscarsson, S. Activity Boost of a Biomimetic Oxidation Catalyst by Immobilization onto a Gold Surface. J. Catal. 2006, 244, 86−91. (147) Hassanein, M.; El-Khalafy, S.; Shendy, S. 5,10,15,20-Tetrakis(4-sulfonatophenyl)porphyrinatocobalt(II) Supported on Ion Exchange Resin as Reusable and Effective Catalyst for the Oxidative Coupling of 2-Aminophenol to 2-Aminophenoxazine-3-one. Catal. Commun. 2013, 40, 125−128. (148) Li, Y. J.; Sun, B. S.; Yang, W. J. Synthesis of Conjugated Mn Porphyrin Polymers with p-Phenylenediamine Building Blocks and Efficient Aerobic Catalytic Oxidation of Alcohols. Appl. Catal., A 2016, 515, 164−169. (149) Zhou, W. Y.; Tian, P.; Sun, F. A.; He, M. Y.; Chen, Q. Highly Efficient Transformation of Alcohol to Carbonyl Compounds Under a Hybrid Bifunctional Catalyst Originated From Metalloporphyrins and Hydrotalcite. J. Catal. 2016, 335, 105−116. (150) Wang, T.; She, Y. B.; Fu, H. Y.; Li, H. Selective Cyclohexane Oxidation Catalyzed by Manganese Porphyrins and Co-Catalysts. Catal. Today 2016, 264, 185−190. (151) Jeong, E. Y.; Ansari, M. B.; Park, S. E. Aerobic Baeyer-Villiger Oxidation of Cyclic Ketones over Metalloporphyrins Bridged Periodic Mesoporous Organosilica. ACS Catal. 2011, 1, 855−863. (152) Zhu, J. H.; Tan, Z. W.; Yang, W. J. Synthesize Polymeric Manganese Porphyrin With CuI/N,N-Dimethyl Glycine acid Catalytic System and High-Efficiency Aerobic Catalytic Oxidation of Cyclic Ketones. Macromol. Res. 2017, 25, 792−798. 10807


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ACS Catalysis (153) Zhou, W. Y.; Tian, P.; Sun, F. A.; He, M. Y.; Chen, Z. X. Efficient Catalysis of the Aerobic Baeyer-Villiger Oxidation over a Bifunctional Catalyst Based on Cobalt Tetraphenylporphyrin Intercalated into Zn2Al Hydrotalcite. Asian J. Org. Chem. 2015, 4, 33−37. (154) Cao, Q.; Yin, Q.; Chen, Q.; Dong, Z. B.; Han, B. H. Fluorinated Porous Conjugated Polyporphyrins through Direct C-H Arylation Polycondensation: Preparation, Porosity, and Use as Heterogeneous Catalysts for Baeyer-Villiger Oxidation. Chem. - Eur. J. 2017, 23, 9831−9837. (155) Zhou, X. T.; Yuan, Q. L.; Ji, H. B. Highly Efficient Aerobic Oxidation of Oximes to Carbonyl Compounds Catalyzed by Metalloporphyrins in the Presence of Benzaldehyde. Tetrahedron Lett. 2010, 51, 613−617. (156) Maid, H.; Bohm, P.; Huber, S. M.; Bauer, W.; Hummel, W.; Jux, N.; Groger, H. Iron Catalysis for In Situ Regeneration of Oxidized Cofactors by Activation and Reduction of Molecular Oxygen: A Synthetic Metalloporphyrin as a Biomimetic NAD(P)H Oxidase. Angew. Chem., Int. Ed. 2011, 50, 2397−2400. (157) Zhou, X. T.; Ji, H. B. Highly Efficient Selective Oxidation of Sulfides to Sulfoxides by Montmorillonite-Immobilized Metalloporphyrins in the Presence of Molecular Oxygen. Catal. Commun. 2014, 53, 29−32. (158) Yun, L.; Zhen, L.; Wang, Z. K.; Fu, X. F. Aerobic Oxidative NDealkylation of Secondary Amines in Aqueous Solution Catalyzed by Rhodium Porphyrins. J. Porphyrins Phthalocyanines 2014, 18, 937− 943. (159) Ohshita, J.; Matsumura, Y.; Nakayama, T.; Yoshida, H.; Kunai, A.; Hisaeda, Y.; Hayashi, T. meso-Tetraaryl(porphyrinato)cobalt(III)Catalyzed Oxygenation of Disilanes under Aerobic Conditions. Chem. Lett. 2017, 46, 1807−1809.

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Metalloporphyrins: Bioinspired Oxidation Catalysts - American

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