- Spectroscopic characterization, X-ray molecular structures and cyclic voltammetry study of two (piperazine) cobalt(II) meso-arylporphyin complexes. Application as a catalyst for the degradation of 4-nitrophenol
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Two new cobaltous-porphyrin complexes, namely (μ-piperazine)-bis[(meso-tetra(para-methoxyphenyl)porphyrinato)]cobalt(II) and (piperazine)[meso-tetra(para-chlorophenyl)porphyrin]cobalt(II) dichloromethane disolvate, with the formulas [{CoII(TMPP)}2(μ2-pipz)] (complex 1) and [CoII(TClPP)(pipz)]·2CH2Cl2 (complex 2), were used efficiently as catalysts in the degradation of 4-nitrophenol (4-NP) in an aqueous hydrogen peroxide solution. These cobalt(II)-pipz porphyrin complexes were characterized by a variety of spectroscopic methods including infrared, UV–visible, fluorescence, proton nuclear magnetic resonance, electron paramagnetic resonance (EPR) as well as mass spectrometry. A cyclic voltammetry investigation was also carried out on these two Co(II) metalloporphyrins. The EPR results indicate that both complexes 1 and 2 are paramagnetic low-spin (S = 1/2) cobalt(II) porphyrin complexes. Furthermore, the X-ray diffraction crystal structures of 1 and 2 were determined, and the intermolecular interactions were investigated by Hirshfeld surface analysis.
- Guergueb, Mouhieddinne,Nasri, Soumaya,Brahmi, Jihed,Al-Ghamdi, Youssef O.,Loiseau, Frédérique,Molton, Florian,Roisnel, Thierry,Guerineau, Vincent,Nasri, Habib
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- Efficient oxidation of cycloalkanes with simultaneously increased conversion and selectivity using O2 catalyzed by metalloporphyrins and boosted by Zn(AcO)2: A practical strategy to inhibit the formation of aliphatic diacids
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The direct sources of aliphatic acids in cycloalkanes oxidation were investigated, and a strategy to suppress the formation of aliphatic acids was adopted through enhancing the catalytic transformation of oxidation intermediates cycloalkyl hydroperoxides to cycloalkanols by Zn(II) and delaying the emergence of cycloalkanones. Benefitted from the delayed formation of cycloalkanones and suppressed non-selective thermal decomposition of cycloalkyl hydroperoxides, the conversion of cycloalkanes and selectivity towards cycloalkanols and cycloalkanones were increased simultaneously with satisfying tolerance to both of metalloporphyrins and substrates. For cyclohexane, the selectivity towards KA-oil was increased from 80.1% to 96.9% meanwhile the conversion was increased from 3.83 % to 6.53 %, a very competitive conversion level with higher selectivity compared with current industrial process. This protocol is not only a valuable strategy to overcome the problems of low conversion and low selectivity lying in front of current cyclohexane oxidation in industry, but also an important reference to other alkanes oxidation.
- Shen, Hai-Min,Wang, Xiong,Ning, Lei,Guo, A-Bing,Deng, Jin-Hui,She, Yuan-Bin
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- Co(II)-porphyrin complexes with nitrogen monoxide and imidazole: synthesis, optimized structures, electrochemical behavior and photochemical stability
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UV-vis and 1H-NMR spectroscopy were applied to study axial coordination of imidazole (L1) and nitrogen monoxide (L2) with CoII-porphyrins (CoIIP) containing halogen substituents in the pyrrole and meso-phenyl positions of
- Kaigorodova, Elena Yu.,Mamardashvili, Galina M.,Simonova, Olga R.,Chizhova, Nataliya V.,Mamardashvili, Nugzar Zh.
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p. 2443 - 2462
(2021/11/10)
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- Efficient oxidation of cumene to cumene hydroperoxide with ambient O2 catalyzed by metalloporphyrins
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A novel and efficient protocol for oxidation of cumene to cumene hydroperoxide was presented using ambient O2 catalyzed by very simple metalloporphyrins. The selectivity toward cumene hydroperoxide reached 98.3% in the cumene conversion of 28.1% with T(4-COOH)PPCu as a catalyst at 80°C. The origin of the higher performance of T(4-COOH)PPCu was mainly ascribed to the low catalytic performance of copper(II) in the cumene hydroperoxide decomposition, and the ability of T(4-COOH)PP in stabilizing cumene hydroperoxide through hydrogen-bond interactions between them. Compared with current industrial processes and academic research in oxidation of cumene to cumene hydroperoxide with O2, the main superiorities of this protocol were the high selectivity, high conversion, simple catalysts, solvent-free, additive-free and mild conditions which made this work an appealing reference for the industrial oxidation of cumene to cumene hydroperoxide, as well as the oxidative functionalization of other C-H bonds in various hydrocarbons. 2021 World Scientific Publishing Company.
- Shen, Hai M.,Ye, Hong L.,Wang, Qin,Hu, Meng Y.,Liu, Lei,She, Yuan B.
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p. 314 - 322
(2021/04/09)
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- Method for synthesizing tetraaryl cobalt porphyrin through synchronous cyclization and metallization
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The invention discloses a method for synthesizing tetraaryl cobalt porphyrin through synchronous cyclization and metallization. Under the catalysis of anhydrous aluminum trichloride, aromatic aldehyde, pyrrole and cobalt salt are subjected to cyclization and metallization reactions synchronously in a DMF solvent and a nitrogen atmosphere to generate the tetraaryl cobalt porphyrin. The reaction process comprises the following steps: sequentially adding anhydrous aluminum trichloride, aryl aldehyde, pyrrole and cobalt salt into DMF while stirring, stopping reaction after heating reflux reactionfor a certain time, cooling, standing overnight near 273K, and carrying out suction filtration to obtain cobalt porphyrin crystals. According to the method, the aromatic aldehyde, the pyrrole and thecobalt salt are directly used as raw materials, porphin is not needed, strongly corrosive organic acid is not used as a solvent, high-purity tetraaryl cobalt porphyrin is obtained at a high yield under the condition that a complex separation means is not needed, and industrial production is easy to achieve.
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Paragraph 0042; 0043
(2020/09/08)
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- Mechanochemical insertion of cobalt into porphyrinoids using Co2(CO)8as a cobalt source
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Cobalt porphyrinoids find broad use as catalysts or electrode materials. Traditional solution state cobalt insertion reactions into a free base porphyrinoid to generate the corresponding cobalt complex generally require fairly harsh conditions, involving the heating of the reactants in high-boiling solvents for extended period of times. We report here an alternative method of cobalt insertion: A solvent-free (at least for the insertion step) mechanochemical method using a planetary ball mill with Co2(CO)8as a cobalt source. The scope and limits of the reaction were investigated with respect to the porphyrinic substrate susceptible to the reaction conditions, the influences of different grinding aids, and bases added. While the mechanochemical method is, like other metal insertion methods into porphyrinoids, not universally suitable for all substrates tested, it is faster, milder, and greener for several others, when compared to established solution-based methods.
- Damunupola, Dinusha,Chaudhri, Nivedita,Atoyebi, Adewole O.,Brückner, Christian
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p. 3643 - 3652
(2020/07/30)
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- Selective Solvent-Free and Additive-Free Oxidation of Primary Benzylic C–H Bonds with O2 Catalyzed by the Combination of Metalloporphyrin with N-Hydroxyphthalimide
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Abstract: A protocol for solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts to overcome the deficiencies encountered in current oxidation systems. The effects of reaction temperature, porphyrin structure, central metal, catalyst loading and O2 pressure were investigated systematically. For the optimized combination of T(2-OCH3)PPCo and NHPI, all the primary benzylic C–H bonds could be functionalized efficiently and selectively at 120 °C and 1.0?MPa O2 with aromatic acids as the primary products. The selectivity towards aromatic acids could reach up to 70–95% in the conversion of more than 30% for most of the substrates possessing primary benzylic C–H bonds in the metalloporphyrin loading of 0.012% (mol/mol). And the superior performance of T(2-OCH3)PPCo among the metalloporphyrins investigated was mainly attributed to its high efficiency in charge transfer and fewer positive charges around central metal Co (II) which favored the adduction of O2 to cobalt (II) forming the high-valence metal-oxo complex followed by the production of phthalimide N-oxyl radical (PINO) and the initiation of the catalytic oxidation cycle. This work would provide not only an efficient protocol in utilization of hydrocarbons containing primary benzylic C–H bonds, but also a significant reference in the construction of more efficient C–H bonds oxidation systems. Graphic Abstract: The solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts, and the highest selectivity towards aromatic acid reached up to 95.1% with the conversion of 88.5% in the optimized combination of T(2-OCH3)PPCo and NHPI.[Figure not available: see fulltext.].
- Shen, Hai-Min,Qi, Bei,Hu, Meng-Yun,Liu, Lei,Ye, Hong-Liang,She, Yuan-Bin
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p. 3096 - 3111
(2020/04/29)
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- Synthesis, Spectral, and Coordination Properties of Halogen-Substituted Tetraarylporphyrins
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2,3,7,8,12,13,17,18-Ocatbromo-5,10,15,20-tetra-(4-chloroprienyl)porphyrin and 2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetra-(4-bromophenyl)porphyrin have been synthesized. The obtained compounds have been identified by electronic absorption and 1/
- Ivanova, Yu. B.,Chizhova,Khrushkova, Yu. V.,Rusanov,Mamardashvili, N. Zh.
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p. 459 - 465
(2019/05/04)
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- Cobalt Tetrabutano- and Tetrabenzotetraarylporphyrin Complexes: Effect of Substituents on the Electrochemical Properties and Catalytic Activity of Oxygen Reduction Reactions
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Three series of cobalt tetraarylporphyrins were synthesized and characterized by electrochemistry and spectroelectrochemistry. The investigated compounds have the general formula (TpYPP)Co, butano(TpYPP)CoII, and benzo(TpYPP)CoII, where TpYPP represents the dianion of the meso-substituted porphyrin, Y is a CH3, H, or Cl substituent on the para position of the four phenyl rings, and butano and benzo are respectively the β- and β′-substituted groups on the four pyrrole rings of the compound. Each porphyrin undergoes one or two reductions depending upon the meso substituent and solvent utilized. Two irreversible reductions are observed for (TpYPP)CoII and butano(TpYPP)CoII in CH2Cl2 containing 0.1 M tetra-n-butylammonium perchlorate; the first leads to the formation of a highly reactive cobalt(I) porphyrin, which can then rapidly react with a solvent to give a CoIIICH2Cl as the product. Only one reversible reduction is seen for benzo(TpYPP)CoII under the same solution conditions, and the one-electron-reduction product is assigned as a cobalt(II) porphyrin π-anion radical. Three oxidations can be observed for each examined compound in CH2Cl2. The first oxidation is metal-centered for the (TpYPP)Co and benzo(TpYPP)CoII derivatives, leading to generation of a cobalt(III) porphyrin with an intact π-ring system, but this redox process is ring-centered in the case of butano(TpYPP)CoII and gives a CoII π-cation radical product. Each porphyrin was also examined as a catalyst for oxygen reduction reactions (ORRs) when adsorbed on a graphite electrode in 1.0 M HClO4. The number of electrons transferred (n) during ORRs is 2.0 for the butano(TpYPP)CoII derivatives, consistent with only H2O2 being produced as a product for the reaction with O2. However, the reduction of O2 using the cobalt benzoporphyrins as catalysts gave n values between 2.6 and 3.1 under the same solution conditions, thus producing a mixture of H2O and H2O2 as the reduction product. This result indicates that the β and β′ substituents have a significant effect on the catalytic properties of the cobalt porphyrins for ORRs in acid media.
- Ye, Lina,Fang, Yuanyuan,Ou, Zhongping,Xue, Songlin,Kadish, Karl M.
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p. 13613 - 13626
(2017/11/15)
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- Synthesis and spectral properties of cobalt(II) and cobalt(III) tetraarylporphyrinates
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Reactions of 5,10,15,20-tetraphenylporphin, 5,10,15,20-tetra(4′- methoxyphenyl)porphyrin, and 5,10,15,20-tetra(4′-chlorophenyl)porphyrin with cobalt(II) acetate in dimethylformamide were studied by spectrophotometry. The corresponding cobalt(II) porphyrin
- Chizhova,Kumeev,Mamardashvili, N. Zh.
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p. 740 - 743
(2013/07/26)
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- Realizing metalloporphyrin functionalization of 4-vinylpyridine copolymer via axial coordination reaction
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Cobalt tetra(para-chlorophenyl)porphyrin (CoTCPP) and zinc tetraphenyl porphyrin (ZnTPP) were linked on the side chains of the copolymer of 4-vinylpyridine (4VP) and styrene (St), P(4VP-co-St), via axial coordination reactions, respectively, and the metalloporphyrin-functionalized macromolecules, CoTCPP-P(4VP-co-St) and ZnTPP-P(4VP-co-St), were prepared. Their chemical structures were characterized by FTIR and 1H NMR. The spectral properties of the two macromolecular axial coordination complexes were mainly studied, and their photophysical behavior were discussed in depth. The experimental results show that the metalloporphyrin-functionalized macromolecules, CoTCPP-P(4VP-co-St) and ZnTPP-P(4VP-co-St), can be prepared favorably through axial coordination reaction with the side pyridine groups of the copolymer P(4VP-co-St) as ligands. The two complexes have characteristic spectra similar to that of the small molecular metalloporphyrins, CoTCPP and ZnTPP, respectively. At the same time, they also display the characteristic spectroscopic property of axial coordination complexes: the electronic adsorption spectra of CoTCPP-P(4VP-co-St) and ZnTPP-P(4VP-co-St) red-shifted obviously as compared to that of CoTCPP and ZnTPP, and the fluorescence emission of ZnTPP-P(4VP-co-St) blue-shifted apparently with respect to that of ZnTPP. For CoTCPP-P(4VP-co-St) and ZnTPP-P(4VP-co-St), some polymer effects were found: (1) The bonding degree of the small molecular metalloporphyrin, CoTCPP or ZnTPP, on the side chains of the copolymer P(4VP-co-St) has a limit value because of the steric hindrance and there is a bonding degree difference between the actual value and the theoretical value; (2) For ZnTPP-P(4VP-co-St), slight energy transfer between adjacent ZnTPP units on an identical macromolecule occurs, leading to slight static quench of the fluorescence emission as the bonding density of ZnTPP units on the side chains of the copolymer P(4VP-co-St) reaches a certain value.
- Gao, Baojiao,Wang, Ruixin,Du, Ruikui
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experimental part
p. 235 - 243
(2010/12/19)
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