New highly brominated Mn-porphyrin: a good catalyst for activation of inert C–H bonds

Silva, Vinicius Santos da; Nakagaki, Shirley; Ucoski, Geani Maria; Idemori, Ynara Marina; DeFreitas-Silva, Gilson

doi:10.1039/c5ra20690a

Cited by 25 publications

(1 citation statement)

References 82 publications

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“…We chose C 4 -symmetry porphyrins with phenyl ( a ), 3-methoxyphenyl ( b ), 4‑methoxyphenyl ( c ), 3,4-dimethoxyphenyl ( d ), and 3,5‑dimethoxyphenyl ( e ) substitutions in the meso -positions. Commercially unavailable dimethoxyphenyl porphyrin derivatives 3d-2H and 3e-2H were synthesized from 1 H -pyrrole and the corresponding aldehyde by a modified synthesis in propionic acid, where nitrobenzene was used to prevent the formation of chlorin. Porphyrins 3d-2H and 3e-2H were obtained in yields of 66 and 64%, respectively.…”

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confidence: 99%

Preparation and Characterization of Metalloporphyrin Tröger’s and Spiro-Tröger’s Base Derivatives

et al. 2022

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A series of metalloporphyrin dimers as Tröger’s bases 1 or spiro-Tröger’s bases 2 was prepared starting from five different C 4-symmetry porphyrin derivatives substituted in meso-positions by Ph, 3-MeO-Ph, 4-MeO-Ph, 3,4-(MeO)2-Ph, or 3,5-(MeO)2-Ph. Free-base porphyrins were converted to metalloporphyrins, which were subsequently nitrated with nickel(II), copper(II), or zinc(II) nitrate to give β-nitrometalloporphyrins. These were further reduced to β-aminometalloporphyrins and treated with a methanal equivalent under acidic conditions to selectively obtain Tröger’s base 1, spiro-Tröger’s base 2, or a mixture of both, in yields up to 41% of 1 and 45% of 2 depending on the reaction conditions used. The ratio of 1 to 2 was influenced by the methanal equivalent used, the strength of the acid, and, above all, the solvent. The presence of a metal ion within the porphyrin core and the use of a chlorinated solvent were found to be essential for the formation of spiro-Tröger’s base 2. The molecular structure of spiroTB 2a-Ni 2 was proven by electron diffraction.

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Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Metalloporphyrin Tröger’s and Spiro-Tröger’s Base Derivatives

et al. 2022

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Manganese‐Catalyzed CH Oxygenation Reactions

Bryliakov

2021

Manganese Catalysis in Organic Synthesis

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Exploring manganese pyridylporphyrin isomers for cyclohexane oxidation: First‐generation catalysts are better than third‐generation ones

Meireles

Guimarães

Querino

et al. 2021

Applied Organom Chemis

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Manganese porphyrins are widely studied as catalysts for oxidation reactions of different organic substrates. In this work, we evaluate the catalytic activity of manganese complexes derived from meso-tetrakis(2-, 3-, or 4-pyridyl) porphyrin isomers, [Mn(TXPyP)]Cl (X = 2, 3, or 4), and the respective β-octabrominated counter-parts, [Mn(Br 8 TXPyP)], for oxidation of cyclohexane by PhI(OAc) 2 . At first, we describe the synthesis and characterization of a new third-generation manganese porphyrin, [Mn(Br 8 T4PyP)]. It presented a more positive value of half-wave potential (À0.287 V vs. Fc + /Fc) and a lower solubility in organic solvents among the isomers. In general, the third-generation catalysts [Mn(Br 8 TXPyP)] showed lower catalytic activity than those of the first-generation [Mn(TXPyP)]Cl in all systems studied. In addition, the use of water or imidazole as cocatalysts did not increase the yield or selectivity of the systems. Finally, when evaluating the use of the classic oxidant PhIO, there was a decrease in yield for all systems, indicating that PhI(OAc) 2 is a good substitute for this oxidant in catalytic systems.

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New highly brominated Mn-porphyrin: a good catalyst for activation of inert C–H bonds

Abstract: Polybrominated Mn-porphyrin can act as a good catalyst for C–H activation. The oxidation of cyclohexane takes place with excellent selectivity and formation of 2-adamantanol is increased in adamantine oxidation.

Cited by 25 publications

References 82 publications

Preparation and Characterization of Metalloporphyrin Tröger’s and Spiro-Tröger’s Base Derivatives

Preparation and Characterization of Metalloporphyrin Tröger’s and Spiro-Tröger’s Base Derivatives

Manganese‐Catalyzed CH Oxygenation Reactions

Exploring manganese pyridylporphyrin isomers for cyclohexane oxidation: First‐generation catalysts are better than third‐generation ones

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