Influence of substituents in meso-aryl groups of iron μ-oxo porphyrins on their catalytic activity in the oxidation of cycloalkanes

Tábor, Edyta; Połtowicz, Jan; Pamin, Katarzyna; Basąg, Sylwia; Kubiak, Władysław W.

doi:10.1016/j.poly.2016.08.048

Cited by 25 publications

(25 citation statements)

References 29 publications

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“…These results are in line with findings reported by Guo for iron μ‐oxo porphyrins in cyclohexane hydroxylation with iodosobenzene as oxygen donor. Our previous studies, which were performed in the presence of manganese or iron porphyrins bearing electron‐donating or electron‐withdrawing groups, also confirmed catalytic activity of Co porphyrins in the oxidation of cyclooctane by molecular oxygen.…”

Section: Resultssupporting

confidence: 61%

“…Recently, we have described the application of both manganese and iron porphyrins as well as their μ‐oxo analogues with different electron‐donating or electron‐withdrawing substituents in the oxidation of cyclooctane to its oxygenates ,. Our investigations demonstrated that these metalloporphyrins are catalytically active in the oxidation process and that their activity depends on the structure of the porphyrin macrocycle.…”

Section: Introductionmentioning

confidence: 91%

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Three Generations of Cobalt Porphyrins as Catalysts in the Oxidation of Cycloalkanes

et al. 2018

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Three generations of cobalt porphyrins were synthesized, physicochemically characterized by FTIR and UV/Vis spectroscopy as well as cyclic voltammetry and applied as catalysts in the oxidation of cycloalkanes with atmospheric molecular oxygen under mild conditions. All examined catalysts were active in the tested reaction, and their catalytic activity varied with the nature and number of substituents on the porphyrin ring. Introduction of electron‐withdrawing or electron‐donating substituents at the porphyrin rings increases the activity of metalloporphyrin complexes. It was found, for the first time, that generation II cobalt porphyrins show higher activity in cycloalkane oxidation than cobalt porphyrins of generation III. The lower catalytic activity of generation III cobalt porphyrins can be attributed to the saddle‐shaped deformation of the porphyrin macrocycle. DFT modeling of Co porphyrins and their interactions with molecular oxygen provided explanations for the observed effects. On the basis of prior reports and the obtained results, a reaction mechanism is proposed and discussed.

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Section: Resultssupporting

confidence: 61%

Section: Introductionmentioning

confidence: 91%

Three Generations of Cobalt Porphyrins as Catalysts in the Oxidation of Cycloalkanes

et al. 2018

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“…This phenomenon is usually called μ 2 ‐oxo‐dimerization. Many previous publications have dealt with the identification and structural characterization of such μ 2 ‐oxo‐bridged Fe 3+ porphyrins owing to their interesting physicochemical properties, such as their catalytic activity in oxidizing alkanes . In some cases, the dimerization process was found to be reversible: treating the monomeric porphyrins with an aqueous basic solution resulted in formation of μ 2 ‐oxo‐bridged dimers, whereas the analogous treatment of the dimers with an aqueous acidic solution led to the breakup into monomeric species .…”

Section: Introductionmentioning

confidence: 99%

“…Many previousp ublicationsh ave dealt with the identification and structuralc haracterization of such m 2 -oxobridged Fe 3 + porphyrins owing to their interesting physicochemicalp roperties, such as their catalytic activity in oxidizing alkanes. [22,23] In some cases, the dimerization process was found to be reversible:t reating the monomeric porphyrins with an aqueous basic solutionr esulted in formation of m 2oxo-bridged dimers,w hereas the analogous treatment of the dimers with an aqueous acidic solution led to the breakupi nto monomeric species. [14] The presence of m 2 -oxo-bridged dimers in solution was provenb ys everalm ethods, for example, electrospray ionization (ESI) mass spectrometry [23][24][25] andu ltraviolet-visible (UV/Vis) spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of μ₂‐Oxo‐Bridged Iron(III) Tetraphenylporphyrin–Spacer–Nitroxide Dimers and their Structural and Dynamics Characterization by using EPR and MD Simulations

Abdullin

Fleck

Klein

et al. 2019

Chemistry A European J

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Iron(III) porphyrins have the propensity to form μ2‐oxo‐dimers, the structures of which resemble two wheels on an axle. Whereas their crystal structure is known, their solution structure and internal dynamics is not. In the present work, the structure and dynamics of such dimers were studied by means of electron paramagnetic resonance (EPR) spectroscopy and quantum chemistry based molecular dynamics (MD) simulations by using the semiempirical tight‐binding method (GFN‐xTB). To enable EPR investigation of the dimers, a nitroxide was attached to each of the tetraphenylporphyrin cores through a linear and a bent linker. The inter‐nitroxide distance distributions within the dimers were determined by continuous‐wave (cw)‐EPR and pulsed electron–electron double resonance (PELDOR or DEER) experiments and, with the help of MD, interpreted in terms of the rotation of the porphyrin planes with respect to each other around the Fe–O–Fe axis. It was found that such rotation is restricted to the four registers defined by the phenyl substituents. Within the registers, the rotation angle swings between 30° and 60° in the proximal and between 125° and 145° in the distal register. With EPR, all four angles were found to be equally populated, whereas the 30° and 145° angles are strongly favored to the expense of the 60° and 125° angles in the MD simulation. In either case, the internal dynamics of these dimers thus resemble the motion of a step motor.

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“…The author also evaluated the effect of peripheral substituents (electron-donating vs. electron-withdrawing), reaction temperature, solvent, and exposure to air on the catalytic activity of the m-oxo heme dimers [60][61][62]. Later, the application of m-oxo heme dimers for direct aerobic oxidation of other hydrocarbons (e.g., cyclopentane, cyclooctane, ethylbenzene or toluene), with the O 2 serving as the terminal oxidant, was investigated [63][64][65]. Guo and coworkers subsequently examined the influence of dioxygen pressure and flow rate in the homogeneous liquid-phase aerobic oxidation of toluene to benzaldehyde, benzyl alcohol, and benzoic acid under conditions similar to those of commercial operations.…”

Section: Oxo-bridged Homobinuclear Homoleptic Systems: [(P)fe III -O-mentioning

confidence: 99%

(Hydr)oxo-bridged heme complexes: From structure to reactivity

Carrasco

Hematian

2019

J. Porphyrins Phthalocyanines

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Iron–porphyrins ([Formula: see text] hemes) are present throughout the biosphere and perform a wide range of functions, particularly those that involve complex multiple-electron redox processes. Some common heme enzymes involved in these processes include cytochrome P450, heme/copper oxidase or heme/non-heme diiron nitric oxide reductase. Consequently, the (hydr)oxo-bridged heme species have been studied for the important roles that they play in many life processes or for their application for catalysis and preparation of new functional materials. This review encompasses important synthetic, structural and reactivity aspects of the (hydr)oxo-bridged heme constructs that govern their function and application. The properties and reactivity of the bridging (hydr)oxo moieties are directly dictated by the coordination environment of the heme core, the nature and ligation of the second metal center attached to the (hydr)oxo group, the presence or absence of a linker, and the degree of flexibility around that linker within the scaffold. Here, we summarize the structural features of all known (hydr)oxo-bridged heme constructs and use those to categorize and thus, provide a more comprehensive picture of structure–function relationships.

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Influence of substituents in meso-aryl groups of iron μ-oxo porphyrins on their catalytic activity in the oxidation of cycloalkanes

Cited by 25 publications

References 29 publications

Three Generations of Cobalt Porphyrins as Catalysts in the Oxidation of Cycloalkanes

Three Generations of Cobalt Porphyrins as Catalysts in the Oxidation of Cycloalkanes

Synthesis of μ₂‐Oxo‐Bridged Iron(III) Tetraphenylporphyrin–Spacer–Nitroxide Dimers and their Structural and Dynamics Characterization by using EPR and MD Simulations

(Hydr)oxo-bridged heme complexes: From structure to reactivity

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Influence of substituents in meso-aryl groups of iron μ-oxo porphyrins on their catalytic activity in the oxidation of cycloalkanes

Cited by 25 publications

References 29 publications

Three Generations of Cobalt Porphyrins as Catalysts in the Oxidation of Cycloalkanes

Three Generations of Cobalt Porphyrins as Catalysts in the Oxidation of Cycloalkanes

Synthesis of μ2‐Oxo‐Bridged Iron(III) Tetraphenylporphyrin–Spacer–Nitroxide Dimers and their Structural and Dynamics Characterization by using EPR and MD Simulations

(Hydr)oxo-bridged heme complexes: From structure to reactivity

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Synthesis of μ₂‐Oxo‐Bridged Iron(III) Tetraphenylporphyrin–Spacer–Nitroxide Dimers and their Structural and Dynamics Characterization by using EPR and MD Simulations