Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Adaptive organic nanoparticles of a teflon-coated iron (III) porphyrin catalytically activate dioxygen for cyclohexene oxidation.

ABSTRACT: Self-organized organic nanoparticles (ONP) are adaptive to the environmental reaction conditions. ONP of fluorous alkyl iron(III) porphyrin catalytically oxidize cyclohexene to the allylic oxidation products. In contrast, the solvated metalloporphyrin yields both allylic oxidation and epoxidation products. The ONP system facilitates a greener reaction because about 89% reaction medium is water, molecular oxygen is used in place of synthetic oxidants, and the ambient reaction conditions used require less energy. The enhanced catalytic activity of these ONP is unexpected because the metalloporphyrins in the nanoaggregates are in the close proximity and the TON should diminish by self-oxidative degradation. The fluorous alkyl chain stabilizes the ONP toward self-oxidative degradation.

SUBMITTER: Aggarwal A

PROVIDER: S-EPMC3697029 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Adaptive organic nanoparticles of a teflon-coated iron (III) porphyrin catalytically activate dioxygen for cyclohexene oxidation.

Aggarwal Amit A Singh Sunaina S Samson Jacopo J Drain Charles Michael CM

Macromolecular rapid communications 20120420 14

Self-organized organic nanoparticles (ONP) are adaptive to the environmental reaction conditions. ONP of fluorous alkyl iron(III) porphyrin catalytically oxidize cyclohexene to the allylic oxidation products. In contrast, the solvated metalloporphyrin yields both allylic oxidation and epoxidation products. The ONP system facilitates a greener reaction because about 89% reaction medium is water, molecular oxygen is used in place of synthetic oxidants, and the ambient reaction conditions used requ ...[more]

PMID: 22517679

Similar Datasets

Bio-Inspired Iron Pentadentate Complexes as Dioxygen Activators in the Oxidation of Cyclohexene and Limonene.

Project description:The use of dioxygen as an oxidant in fine chemicals production is an emerging problem in chemistry for environmental and economical reasons. In acetonitrile, the [(N4Py)FeII]2+ complex, [N4Py-N,N-bis(2-pyridylmethyl)-N-(bis-2-pyridylmethyl)amine] in the presence of the substrate activates dioxygen for the oxygenation of cyclohexene and limonene. Cyclohexane is oxidized mainly to 2-cyclohexen-1-one, and 2-cyclohexen-1-ol, cyclohexene oxide is formed in much smaller amounts. Limonene gives as the main products limonene oxide, carvone, and carveol. Perillaldehyde and perillyl alcohol are also present in the products but to a lesser extent. The investigated system is twice as efficient as the [(bpy)2FeII]2+/O2/cyclohexene system and comparable to the [(bpy)2MnII]2+/O2/limonene system. Using cyclic voltammetry, it has been shown that, when the catalyst, dioxgen, and substrate are present simultaneously in the reaction mixture, the iron(IV) oxo adduct [(N4Py)FeIV=O]2+ is formed, which is the oxidative species. This observation is supported by DFT calculations.

| S-EPMC10004738 | biostudies-literature

The [(Bn-tpen)Fe<sup>II</sup>]<sup>2+</sup> Complex as a Catalyst for the Oxidation of Cyclohexene and Limonene with Dioxygen.

Project description:[(Bn-tpen)FeII(MeCN)](ClO4)2, containing the pentadentate Bn-tpen-N-benzyl-N,N',N'-tris(2-pyridylmethyl)-1,2-diaminoethane ligand, was studied in the oxygenation of cyclohexene and limonene using low-pressure dioxygen (0.2 atm air or 1 atm pure O2) in acetonitrile. 2-Cyclohexen-1-one and 2-cyclohexen-1-ol are the main products of cyclohexene oxidations, with cyclohexene oxide as a minor product. Limonene is oxidized to limonene oxide, carvone, and carveol. Other oxidation products such as perillaldehyde and perillyl alcohol are found in trace amounts. This catalyst is slightly less active than the previously reported [(N4Py)FeII(MeCN)](ClO4)2 (N4Py-N,N-bis(2-pyridylmethyl)-N-(bis-2-pyridylmethyl)amine). Based on cyclic voltammetry experiments, it is postulated that [(Bn-tpen)FeIV=O]2+ is the active species. The induction period of approx. 3 h during cyclohexene oxygenation is probably caused by deactivation of the reactive Fe(IV)=O species by the parent Fe(II) complex. Equimolar mixtures of Fe(II) salt and the ligand (in situ-formed catalyst) gave catalytic performance similar to that of the synthesized catalyst.

| S-EPMC11357577 | biostudies-literature

Kinetics and mechanism of oxidation reactions of porphyrin-iron(IV)-oxo intermediates.

Project description:The kinetics of the reactions of three porphyrin-iron(IV)-oxo derivatives with alkenes and benzylic alcohols were measured. The iron-oxo systems studied were 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin-iron(IV)-oxo (2a), 5,10,15,20-tetrakis(2,6-difluorophenyl)porphyrin-iron(IV)-oxo (2b), and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin-iron(IV)-oxo (2c). Species 2 were stable for hours at room temperature as dilute solutions in acetonitrile and reacted hundreds to thousands of times faster in the presence of high concentrations of substrates. Typical second-order rate constants determined from pseudo-first-order kinetic studies are 1-2 x 10(-2) M(-1) s(-1) for reactions with styrene and 3 x 10(-2) M(-1) s(-1) for reactions with benzyl alcohol. The reactivity order for the iron-oxo species was 2a > 2b > 2c, which is inverted from that expected on the basis of the electron demand of the porphyrin macrocycles, and the oxidation reaction was suppressed when excess porphyrin-iron(III) complex was added to reaction mixtures. These observations indicate that the reactions involve disproportionation of the iron(IV)-oxo species 2 to give an iron(III) species and a more highly oxidized iron species, presumed to be an iron(IV)-oxo porphyrin radical cation, that is the true oxidant in the reactions. Analyses of the kinetics of oxidations of a series of para-substituted benzylic alcohols with Hammett sigma+ -substituent constants and with a dual-parameter method developed by Jiang (Jiang, X. K. Acc. Chem. Res. 1997, 30, 283) indicated that considerable positive charge developed on the benzylic carbons in the oxidation reactions, as expected for electrophilic oxidants, and also that substantial radical character developed on the benzyl carbon in the transition states.

| S-EPMC2907147 | biostudies-literature

Stable and catalytically active iron porphyrin-based porous organic polymer: Activity as both a redox and Lewis acid catalyst.

Project description:A new porphyrin-based porous organic polymer (POP) with BET surface area ranging from 780 to 880 m(2)/g was synthesized in free-base form via the reaction of meso-tetrakis(pentafluorophenyl) porphyrin and a rigid trigonal building block, hexahydroxytriphenylene. The material was then metallated with Fe(III) imparting activity for Lewis acid catalysis (regioselective methanolysis ring-opening of styrene oxide), oxidative cyclization catalysis (conversion of bis(2-hydroxy-1-naphthyl)methanes to the corresponding spirodienone), and a tandem catalytic processes: an in situ oxidation-cyclic aminal formation-oxidation sequence, which selectively converts benzyl alcohol to 2-phenyl-quinazolin-4(3H)-one. Notably, the catalyst is readily recoverable and reusable, with little loss in catalytic activity.

| S-EPMC4503946 | biostudies-literature

Oxidation of an indole substrate by porphyrin iron(iii) superoxide: relevance to indoleamine and tryptophan 2,3-dioxygenases.

Project description:Reaction of FeIII(O2?-)(TPP) with 2,3-dimethylindole at -40 °C gives the ring-opened, dioxygenated N-(2-acetyl-phenyl)-acetamide product. The reaction was monitored in situ by low-temperature UV-vis and 1H NMR spectroscopies. This work demonstrates that a discrete iron(iii)(superoxo) porphyrin is competent to carry out indole oxidation, as proposed for the tryptophan and indoleamine 2,3-dioxygenases.

| S-EPMC7065957 | biostudies-literature

Hexamodal imaging with porphyrin-phospholipid-coated upconversion nanoparticles.

Project description:Hexamodal imaging using simple nanoparticles is demonstrated. Porphyrin-phospholipids are used to coat upconversion nanoparticles in order to generate a new biocompatible material. The nanoparticles are characterized in vitro and in vivo for imaging via fluorescence, upconversion, positron emission tomography, computed tomography, Cerenkov luminescence, and photoacoustic tomography.

| S-EPMC4416944 | biostudies-literature

Selective Catalytic Oxidation of Cyclohexene with Molecular Oxygen: Radical Versus Nonradical Pathways.

Project description:We study the allylic oxidation of cyclohexene with O2 under mild conditions in the presence of transition-metal catalysts. The catalysts comprise nanometric metal oxide particles supported on porous N-doped carbons (M/N:C, M=V, Cr, Fe, Co, Ni, Cu, Nb, Mo, W). Most of these metal oxides give only moderate conversions, and the majority of the products are over-oxidation products. Co/N:C and Cu/N:C, however, give 70-80?% conversion and 40-50?% selectivity to the ketone product, cyclohexene-2-one. Control experiments in which we used free-radical scavengers show that the oxidation follows the expected free-radical pathway in almost all cases. Surprisingly, the catalytic cycle in the presence of Cu/N:C does not involve free-radical species in solution. Optimisation of this catalyst gives >85?% conversion with >60?% selectivity to the allylic ketone at 70?°C and 10?bar O2. We used SEM, X-ray photoelectron spectroscopy and XRD to show that the active particles have a cupric oxide/cuprous oxide core-shell structure, giving a high turnover frequency of approximately 1500?h-1. We attribute the high performance of this Cu/N:C catalyst to a facile surface reaction between adsorbed cyclohexenyl hydroperoxide molecules and activated oxygen species.

| S-EPMC5873426 | biostudies-literature

Manganese(II) complexes with Bn-tpen as powerful catalysts of cyclohexene oxidation.

Project description:Manganese(II) complex [(Bn-tpen)MnII]2+ activated dioxygen for oxidation of cyclohexene in acetonitrile (MeCN) and methanol (MeOH). In MeCN, ketone (2-cyclohexen-1-one), alcohol (2-cyclohexen-1-ol) and small amounts of epoxide (cyclohexene oxide) were produced in this reaction, while in MeOH only ketone was formed. In the most efficient experiment, the combination of 2.5 × 10-4 mol% [(Bn-tpen)MnII]2+ and 4 M cyclohexene under dioxygen atmosphere (pO2 = 1 atm) in MeCN after 24 h of reaction, gave the TON equal to 716, and the main oxidation products were ketone (196 mM) and alcohol (147 mM), whereas epoxide was formed in insignificant amounts (15 mM). The formation of [(Bn-tpen)MnIV=O]2+ and [(Bn-tpen)MnIII-OH]2+ species was confirmed. The novelty of this work is the observation, that in both solvents, [(Bn-tpen)MnII]2+ complex is initially oxidized by t-BuOOH to produce Mn(III)-complex, which is reduced back by cyclohexene to [(Bn-tpen)MnII]2+, and the latter species is an active catalyst of c-C6H10 oxidation. Knowledge of the electrochemical properties of the system components may contribute to understanding the mechanisms involving participation of the active agents created in the system.

| S-EPMC5655609 | biostudies-literature

Dioxygen Reactivity of Copper(I)/Manganese(II)-Porphyrin Assemblies: Mechanistic Studies and Cooperative Activation of O2.

Project description:The oxidation of transition metals such as manganese and copper by dioxygen (O2) is of great interest to chemists and biochemists for fundamental and practical reasons. In this report, the O2 reactivities of 1:1 and 1:2 mixtures of [(TPP)MnII] (1; TPP: Tetraphenylporphyrin) and [(tmpa)CuI(MeCN)]+ (2; TMPA: Tris(2-pyridylmethyl)amine) in 2-methyltetrahydrofuran (MeTHF) are described. Variable-temperature (-110 °C to room temperature) absorption spectroscopic measurements support that, at low temperature, oxygenation of the (TPP)Mn/Cu mixtures leads to rapid formation of a cupric superoxo intermediate, [(tmpa)CuII(O2•-)]+ (3), independent of the presence of the manganese porphyrin complex (1). Complex 3 subsequently reacts with 1 to form a heterobinuclear μ-peroxo species, [(tmpa)CuII-(O22-)-MnIII(TPP)]+ (4; λmax = 443 nm), which thermally converts to a μ-oxo complex, [(tmpa)CuII-O-MnIII(TPP)]+ (5; λmax = 434 and 466 nm), confirmed by electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. In the 1:2 (TPP)Mn/Cu mixture, 4 is subsequently attacked by a second equivalent of 3, giving a bis-μ-peroxo species, i.e., [(tmpa)CuII-(O22-)-MnIV(TPP)-(O22-)-CuII(tmpa)]2+ (7; λmax = 420 nm and δpyrrolic = -44.90 ppm). The final decomposition product of the (TPP)Mn/Cu/O2 chemistry in MeTHF is [(TPP)MnIII(MeTHF)2]+ (6), whose X-ray structure is also presented and compared to literature analogs.

| S-EPMC8839022 | biostudies-literature

A stable hyponitrite-bridged iron porphyrin complex.

Project description:The coupling of two nitric oxide (NO) molecules in heme active sites is an important contributor to the conversion of NO to nitrous oxide (N(2)O) by heme-containing enzymes. Several formulations for the presumed heme-Fe{N(2)O(2)}(n-) intermediates have been proposed previously, however, no crystal structures of heme-Fe{N(2)O(2)}(n-) systems have been reported to date. We report the first isolation and characterization of a stable bimetallic hyponitrite iron porphyrin, [(OEP)Fe](2)(mu-N(2)O(2)), prepared from the reaction of [(OEP)Fe](2)(mu-O) with hyponitrous acid. Density functional theoretical calculations were performed on the model compound [(porphine)Fe](2)(mu-N(2)O(2)) to characterize its electronic structure and properties.

| S-EPMC2676163 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data