- Oxidation of olefins and sulfides with different oxidants catalyzed by meso-tetra(n-propyl)porphyrinatomanganese(III) acetate: Comparison with meso-tetra(phenyl)porphyrinatomanganese(III) acetate
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In this study, the catalytic activity of meso-tetra(n-propyl)porphyrinatomanganese(III) acetate, MnT(n-pr)(OAc) in oxidation of olefins and sulfides with tetra-n-butylammonium Oxone (TBAO), tetra-n-butylammonium periodate (TBAP), aqueous hydrogen peroxide, sodium periodate and Oxone in the presence of imidazole (ImH) has been studied. The comparison of catalytic performance of MnT(n-pr)P(OAc) and MnTPP(OAc) in oxidation of olefins with TBAP shows that while the latter is four times more efficient than the former, the extent of oxidative degradation of the former is ca. 3.5 times greater than the latter. The use of excess amount of styrene resulted in only a ca. 10 % increase in the catalyst stability, suggesting a mainly intramolecular mechanism for the catalyst degradation. On the other hand, in the case of TBAO, the oxidative degradation of the former is four times greater than the latter, but the catalytic performance of the latter for the oxidation of cyclohexene was only ca. 2 times larger than the former. This observation shows that the decreased catalytic performance of MnT(n-pr)P(OAc) relative to MnTPP(OAc) is essentially due to the high degree of degradation of the former. Due to the high degree of catalyst degradation, oxidation of olefins with periodate and Oxone in the presence of the two manganese porphyrins in aqueous solution (or with hydrogen peroxide in dichloromethane) gave little or no product. Oxidation of sulfides with TBAO and TBAP in the presence of MnT(n-pr)P(OAc) showed a conversion of ca. 15 % for the catalytic oxidation of sulfides to sulfones.
- Zakavi, Saeed,Fathi, Mahdieh
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- Partial and full β-bromination of meso-tetraphenylporphyrin: Effects on the catalytic activity of the manganese and nickel complexes for photo oxidation of styrene in the presence of molecular oxygen and visible light
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A series of β-brominated meso-tetraphenylporphyrins, H2TPPBrx (x = 0, 4, 8) have been synthesized and the photocatalytic activity of their manganese (III) and nickel (II) complexes in photo oxidation of styrene was thoroughly investi
- Esfandiar, Milad,Saadati, Saeedeh
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- Method and device for preparing metalloporphyrin compound
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The invention discloses a method and a device for preparing a metalloporphyrin compound. The method comprises the following steps: using a porphyrin and a transition metal acetic acid aqueous salt ora chloride aqueous salt as raw materials, performing a reflux reaction on a metallization reaction device, and using thin layer chromatography (TLC) or UV-Vis spectroscopy (UV-Vis) to monitor the reaction process until porphyrin is completely reacted, distilling off a solvent from the reaction product and washing with water and recrystallizing to obtain the product. due to a higher conjugated structure, the single metalloporphyrin polymer shows better electrocatalytic activity of an oxygen reduction reaction, can catalyze oxygen reduction reaction in acidic, basic or neutral electrolytes, andhas good stability and methanol resistance. The large-scale synthesis method of metalloporphyrin has good social and economic benefits, high yield, low production cost and easy separation of products.
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Paragraph 0035; 0036; 0037; 0038
(2019/05/08)
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- Nanoaggregates of simple Mn porphyrin complexes as catalysts for the selective oxidation of hydrocarbons
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A stable suspension of simple manganese(III) meso-tetraphenylporphyrin nanoaggregates was prepared by a host-guest procedure, in which ethanol and water are used as "green" solvents. The organic nanoparticles were studied by dynamic light scattering (DLS), AFM, and UV/Vis and fluorescence spectroscopy. The results indicate that the nanoaggregates have a spherical morphology with sizes between 15-40 nm. The epoxidation of olefins and oxygenation of saturated hydrocarbons by PhI(OAc)2 were efficiently enhanced with excellent selectivity under the influence of simple Mn(TPP)OAc (TPP = meso-tetraphenylporphyrin) nanoparticles. Enhanced stabilities and activities were achieved with nanostructured Mn catalysts compared to those of the individual counterparts in solution according to turnover numbers and UV/Vis studies. The title nanocatalyst facilitates a greener reaction because the reaction solvent is a water/ethanol mixture and PhI(OAc)2 is safe to use. The efficiency of the oxidation system depends critically upon the steric hindrances and electronic structures of both nitrogen donor ligands and porphyrin nanoparticles. Copyright
- Rezaeifard, Abdolreza,Soltani, Vahideh,Jafarpour, Maasoumeh
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p. 2657 - 2664
(2013/06/05)
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- A convenient, high-yielding, chromatography-free method for the insertion of transition metal acetates into porphyrins
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Presented is a quick and efficient method for the insertion of first-row transition metal acetates into 5,10,15,20-tetraphenyl porphyrin, utilizing Soxhlet extraction for the removal of the acetic acid by-product. High yields (>90%) and purity are achieved without requiring chromatographic purification. Basic Mn(III) and Fe(III) acetate may be used, as well as hydrated Co(II), Ni(II), and Cu(II) acetates as starting materials. In the case of Fe, an initial mixture of Fe(TPP)OAc and [Fe(TPP)]2O is formed, which can be quantitatively converted to Fe(TPP)OAc by treatment with acetic acid. The crystal structure of Fe(TPP)OAc is reported, and spectral data for all compounds is presented, including a correction of the literature UV- Vis data for Fe(TPP)OAc. Attempted metalation with basic Cr(III) acetate yielded a mixture of Cr(TPP)OAc and the oxo-bridged dimer. The latter cannot be converted to the desired acetate. No reaction occurred with vanadyl or titanyl acetate under the conditions used.
- Yao, Shu A.,Hansen, Christopher B.,Berry, John F.
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- Ultrasound and ionic liquid: An efficient combination to tune the mechanism of alkenes epoxidation
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In this proof of concept study, the advantageous properties of both H 2O2/NaHCO3/imidazole/Mn(TPP)OAc oxidation system and MOPyrroNTf2 ionic liquid have been combined under ultrasonic irradiation to give an exceptionally favorable environment for Mn(TPP)OAc catalyzed olefin oxidations. The results reveal the crucial role played by the ultrasonic irradiations that influence drastically the oxidation process. In MOPyrroNTf2 and under ultrasonic irradiation, the mechanism probably involves an oxo-manganyl intermediate at the expense of the classical bicarbonate-activated peroxide route.
- Chatel, Gregory,Goux-Henry, Catherine,Kardos, Nathalie,Suptil, Joel,Andrioletti, Bruno,Draye, Micheline
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experimental part
p. 390 - 394
(2012/04/23)
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- Effects of methoxy-substituted metalloporphyrins in catalytic alkene epoxidation by n-Bu 4NHSO 5
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TPPMnOAc and four different kinds of manganese tetraphenylporphyrin acetates were synthesized using different numbers of methoxy substituents in various positions of the phenyl rings. These porphyrins were used as catalysts in the epoxidation of various alkenes with tetra-n-butylammonium hydrogen monopersulfate (n-Bu 4NHSO 5) as the oxidant and imidazole as the axial base. The following order of catalytic activity was obtained: TPPMnOAc ≥ T(2,3-OMeP) PMnOAc > T(4-OMeP) PMnOAc > T(3,4-OMeP) PMnOAc > T(2,4,6-OMeP) PMnOAc. By studying the UV-vis spectra in the reaction solution, the stability of the applied methoxy porphyrins and the effect of this factor on obtained yields were investigated. Lower catalytic activity in some of the methoxy porphyrins emphasized steric effects and special hydrogen bonding among the reaction elements. However, the stability of T(2,3-OMeP) PMnOAc under our reaction condition was considerable and high activity was observed. By adding small amounts of alcohol to the reaction solution, the effect of the solvent mixture was previewed and steps were taken to identify the active intermediate of the catalyst in these conditions. Copyright
- Aghabali, Amineh,Safari, Nasser
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experimental part
p. 335 - 342
(2010/11/21)
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- The patterns of nitrogen atom transfer between manganese(V) and manganese(III) complexes with porphyrins and tetraazaporphyrins
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The kinetics of intermetallic nitride nitrogen atom transfer between manganese(V) and manganese(III) complexes with tetraphenylporphin and octaphenyltetraazaporphin were studied. The interaction between the nitridomanganese(V)tetraphenylporphyrin and Mn(I
- Stuzhin,Repina,Klyueva,Fedotova
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p. 864 - 870
(2007/10/03)
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- The use of perchlorato(tetraphenylporphinato)manganese(III) as a reagent for the spectrophotometric determination of anions in nonaqueous solvents
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Perchlorato(tetraphenylporphinato)manganese(III) (TPPMnClO4) is shown to be a useful reagent for the determination of a variety of anions in nonaqueous media.The analysis is based on the displacement of coordinated perchlorate by more strongly coordinating anions as monitored spectrophotometrically.The procedure is demonstrated for the determination of tetra-alkylammonium salts of nitrate, nitrite, chloride, bromide, iodide, acetate, trifluoroacetate, cyanate, and thiocyanate in acetonitrile.Relative precisions and accuracies of the order of five parts per thousand are indicated.Key words: perchlorato(tetraphenylporphinato)manganese(III), spectrophotometric determination of anions, anions in nonaqueous media.
- Hinman, A. Scott,McGarty, Karen,Tang, Clement,Pavelich, Brad J.
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p. 545 - 550
(2007/10/02)
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- Electrochemical reactivity of manganese(II) porphyrins. Effects of dioxygen, benzoic anhydride, and axial ligands
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Currents for electrochemical reductions of manganese(III) porphyrins in oxygenated, aprotic media correspond to passage of between one and two electrons per porphyrin, depending on the experimental time scale, the axial base present, and the particular porphyrin. The two-electron process corresponds to an ECE reaction sequence involving formation and subsequent reduction of an intermediate Mn(II)-dioxygen adduct. The formal potential of the second electron step is shown to be ca. -0.17 V vs. NaSCE for Mn(TPP)benzoate. Passage of the second electron is suppressed by strong axial bases and by competitive axial binding but is promoted by use of an axial anion that gives the most negative potential for passage of the first electron, Mn(TPP)benzoate being a specific example. The overall rate constant for the intermediate chemical step is estimated. In the presence of the added electrophile benzoic anhydride, and on a slower time scale, reduction by more than two electrons occurs by a process postulated to involve heterolysis of the O-O bond by the electrophile, producing an even more easily reduced, high-valent manganese-oxo porphyrin. The rate of electrophile attack is slower than that for dioxygen binding.
- Creager,Murray, Royce W.
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p. 2612 - 2618
(2008/10/08)
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- Study of (Tetraphenylporphinato)manganese(III)-Catalyzed Epoxidation and Demethylation Using p-Cyano-N,N-dimethylaniline N-Oxide as Oxygen Donor in a Homogeneous System. Kinetics, Radiochemical Ligation Studies, and Reaction Mechanism for a Model of Cytochrome P-450
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Oxygen transfer from p-cyanodimethylaniline (p-CNDMANO) to cyclohexene as well as "intramolecular" oxygen transfer accompained by demethylation to yield p-cyanomonomethylaniline (p-CNMMA) are strongly catalyzed by ligated (tetraphenylporphinato)MnIII (i.e., XMnIIITPP).These reactions have been studied in dry, oxygen-free benzonitrile.Radiochemical studies show that H2O (or TOH) is not bound to XMnIIITPP in aprotic solvents so that the MnIII moiety is pentacoordinate.Oxygen transfer occurs through the reversible formation of the hexacoordinated species p-CNDMANO*MnIII(X)TPP.This species decomposes to p-cyanodimethylaniline (p-CNDMA) + O=MnV(X)TPP.Reactions of cyclohexene with O=MnV(X)TPP yields cyclohexene epoxide and XMnIIITPP whereas p-CNMMA is formed directly from the p-CNDMANO*MnIII(X)TPP complex.The rates of product formation are shown to be dependent upon the nature of the ligand (X- = F-, Cl-, Br-, I-, OCN-).In the absence of the axial ligand X-, the rates of reaction are extremely slow.Thus, the MnIII C2-cap-porphyrin (XMnIIICAPTPP), which can only form an O=MnV porphyrin species wherein the Mn moiety is not complexed to X- as a sixth ligand, shows almost no tendency to act as a catalyst for oxygen transfer.The necessary presence of the axial ligand X- and the dependence of rate upon X- requires the structure of the oxygen transfer species to be quivalent to O=MnV(X)TPP.A kinetic analysis is presented (Scheme III) which has allowed the determination of the influence of the ligands X- upon the various rate constants (Table IV) involved in the overall oxidations.By employing p-CNDMANO as oxygen donor, multiple catalytic turnovers without loss of porphyrin have been realized.
- Powell, Michael F.,Pai, Emil F.,Bruice, Thomas C.
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p. 3277 - 3285
(2007/10/02)
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