16456-81-8Relevant articles and documents
Electrochemical analysis of iron-porphyrin-catalyzed CO2 reduction under photoirradiation
Fukatsu, Arisa,Kondo, Mio,Okabe, Yuki,Masaoka, Shigeyuki
, p. 143 - 148 (2015)
In this study, the photochemical reaction of a metal-complex-based catalyst was analyzed by electrochemical measurements. A well-known catalyst for the CO2 reduction reaction, meso-tetraphenylporphyrin iron(III) chloride (Fe(tpp)Cl), was selected as the target analyte. Although the analysis of the electrochemical response of Fe(tpp)Cl under photoirradiation with conventional cyclic voltammetry (CV) was not allowed, the adaptation of thin layer cyclic voltammetry (TLCV) enabled us to detect the photochemical reaction of Fe(tpp)Cl. The influence of photoirradiation on the electrochemical property of Fe(tpp)Cl was investigated both under Ar and CO2 atmospheres. Although the thin layer cyclic voltammograms of Fe(tpp)Cl upon photoirradiation under an Ar atmosphere were almost the same as those measured in the dark, the measurements under a CO2 atmosphere clearly indicated the change of the electrochemical response upon photoirradiation. The detailed analysis of this phenomenon revealed that the photoinduced decarbonylation reaction regenerates the original [FeII(tpp)] complex under photoirradiation.
Synthesis, electrochemical and spectroelectrochemical characterization of iron(III) tetraarylporphyrins containing four β, β ′-butano and β, β ′-benzo fused rings
Xu, Weijie,Fang, Yuanyuan,Ou, Zhongping,Chen, Mingyuan,Kadish, Karl M.
, p. 521 - 534 (2018)
Six iron(III) tetraarylporphyrins containing four b,b?-butano or b,b?-benzo fused rings were synthesized and characterized by electrochemistry and spectroelectrochemistry in nonaqueous media. The examined compounds are represented as butano(TpYPP)FeCl and
Immobilization of Fe, Mn and Co tetraphenylporphyrin complexes in MCM-41 and their catalytic activity in cyclohexene oxidation reaction by hydrogen peroxide
Costa, Andréia A.,Ghesti, Grace F.,de Macedo, Julio L.,Braga, Valdeilson S.,Santos, Marcello M.,Dias, José A.,Dias, Sílvia C.L.
, p. 149 - 157 (2008)
Metalloporphyrin catalysts are able to carry out selective oxidation of organic substrates with several oxidizing agents. Recently, mesoporous materials have been studied as supports because they present high specific surface area, better dispersion and regeneration properties. This work presents the results of synthesis, characterization and application of three metalloporphyrin catalysts (FeTPPCl, MnTPPCl and CoTPP, where TPP = tetraphenylporphyrin) anchored on MCM-41, in the reaction of cyclohexene oxidation with hydrogen peroxide. A modified sol-gel preparation was chosen for the synthesis of the MCM-41 mesoporous material, as well as the anchoring was followed by Soxhlet extraction to ensure strong adsorption of the complex. The supported materials were much more stable than pure metalloporphyrins. The synthesized catalysts were characterized by UV-vis, FTIR, XRD, ICP-AES, 29Si MAS-NMR and thermal analysis, before and after incorporation. Evidence of the metalloporphyrin immobilization was confirmed by elemental analysis and their activity in the oxidation reaction. FeTPPCl/MCM-41 showed higher conversion than CoTPP/MCM-41 and MnTPPCl/MCM-41. However, MnTPPCl/MCM-41 even in low concentration on the support showed a good conversion for the direct oxidation of cyclohexene with the highest turnover number (1.54 × 105). All catalysts showed similar selectivity that favors allylic oxidation products over epoxidation. No leaching of the metalloporphyrins was observed after the reaction.
The Formation of Heterobinuclear μ-Oxo Cr-O-Fe Porphyrin Complexes by the Reaction of Oxochromium(IV) and Iron(II) Porphyrins
Liston, David J.,Murray, Keith S.,West, Bruce O.
, p. 1109 - 1111 (1982)
The reaction of α,β,γ,δ-tetraphenylporphinato-oxochromium(IV) with α,β,γ,δ-tetraphenylporphinato-iron(II)bis(piperidine) in toluene results in the formation of the mixed-metal complex (TPP)CrIII-O-FeIII(TPP) characterised
Hydrogen bonding in metalloporphyrin reactions. Reaction of (tetraphenylporphinato)iron(III) chloride and N-methylimidazole
Doeff, Marca M.,Sweigart
, p. 3699 - 3705 (1982)
The reaction of N-methylimidazole, N-MeIm, and high-spin five-coordinate (tetraphenylporphinato)iron(III) chloride, Fe(TPP)Cl, proceeds rapidly to form low-spin Fe(TPP)(N-MeIm)2+Cl-. During the reaction an intermediate mono(imidazole) complex, Fe(TPP)(N-MeIm)Cl, can be detected as a transient at room temperature and can be trapped for longer periods at low temperatures. The optical spectrum, ESR spectrum, and formation constant of the intermediate show it to be a high-spin six-coordinate species, proving that a spin change occurs upon addition of the second N-MeIm to form Fe-(TPP)(N-MeIm)2+Cl-. Kinetic studies in several solvents show that the rate-determining step in the reaction of N-MeIm and Fe(TPP)Cl is chloride ionization from the mono(imidazole) intermediate. The chloride ionization rate constant, k1, is strongly dependent on the ability of the solvent to hydrogen bond to the departing chloride in the transition state as shown by a very good correlation of k1 with Gutmann acceptor numbers for six solvents. Correlations do not exist with other common solvent parameters such as dielectric constant. Low concentrations of potential hydrogen bonders like trifluoroethanol and phenol have a large accelerating effect on k1. The relationship between this work and possible hydrogen bonding involving distal and proximal histidines in hemoprotein-mediated reactions is discussed.
Dioxygen Activation in the Photochemistry of some Oxo-metalloporphyrin Complexes
Bergamini, Paola,Sostero, Silvana,Traverso, Orazio,Deplano, Paola,Wilson, Lon J.
, p. 2311 - 2314 (1986)
Ultraviolet irradiation of the peroxo-complexes and (tpp = 5,10,15,20-tetraphenylporphyrinate) induces elimination of O2 and generation of the corresponding oxometalloporphyrins and .Reductive elimination o
Construction of secondary coordination sphere boosts electrochemical CO 2 reduction of iron porphyrins
Liu, Guiyu,Fan, Ying-Jie,Zhang, Jun-Long
, p. 465 - 472 (2020)
Iron porphyrins with simple aminophenyl substitution are synthesized and their electrochemical CO2 reduction properties are studied. Fe-1, bearing an amino group in the ortho position of the phenyl ring exhibits an improved catalytic turn over frequency (
Syntheses and CO2 reduction activities of π-expanded/extended iron porphyrin complexes
Okabe, Yuki,Lee, Sze Koon,Kondo, Mio,Masaoka, Shigeyuki
, p. 713 - 725 (2017)
The construction of molecular catalysts that are active toward CO2 reduction is of great significance for designing sustainable energy conversion systems. In this study, we aimed to develop catalysts for CO2 reduction by introducing
Quick and Easy Method to Dramatically Improve the Electrochemical CO2 Reduction Activity of an Iron Porphyrin Complex
Kondo, Mio,Kosugi, Kento,Masaoka, Shigeyuki
, p. 22070 - 22074 (2021)
The development of artificial molecular catalysts for CO2 reduction is the key to solving energy and environmental problems. Although chemical modifications can generally improve the catalytic activity of this class of compounds, they often req
Mechanism of Catalytic O2 Reduction by Iron Tetraphenylporphyrin
Pegis, Michael L.,Martin, Daniel J.,Wise, Catherine F.,Brezny, Anna C.,Johnson, Samantha I.,Johnson, Lewis E.,Kumar, Neeraj,Raugei, Simone,Mayer, James M.
, p. 8315 - 8326 (2020)
The catalytic reduction of O2 to H2O is important for energy transduction in both synthetic and natural systems. Herein, we report a kinetic and thermochemical study of the oxygen reduction reaction (ORR) catalyzed by iron tetraphenylporphyrin (Fe(TPP)) in N,N′-dimethylformamide using decamethylferrocene as a soluble reductant and para-toluenesulfonic acid (pTsOH) as the proton source. This work identifies and characterizes catalytic intermediates and their thermochemistry, providing a detailed mechanistic understanding of the system. Specifically, reduction of the ferric porphyrin, [FeIII(TPP)]+ , forms the ferrous porphyrin, FeII(TPP), which binds O2 reversibly to form the ferricsuperoxide porphyrin complex, FeIII(TPP)(O2 ?-). The temperature dependence of both the electron transfer and O2 binding equilibrium constants has been determined. Kinetic studies over a range of concentrations and temperatures show that the catalyst resting state changes during the course of each catalytic run, necessitating the use of global kinetic modeling to extract rate constants and kinetic barriers. The rate-determining step in oxygen reduction is the protonation of FeIII(TPP)(O2 ?-) by pTsOH, which proceeds with a substantial kinetic barrier. Computational studies indicate that this barrier for proton transfer arises from an unfavorable preassociation of the proton donor with the superoxide adduct and a transition state that requires significant desolvation of the proton donor. Together, these results are the first example of oxygen reduction by iron tetraphenylporphyrin where the pre-equilibria among ferric, ferrous, and ferric-superoxide intermediates have been quantified under catalytic conditions. This work gives a generalizable model for the mechanism of iron porphyrin-catalyzed ORR and provides an unusually complete mechanistic study of an ORR reaction. More broadly, this study also highlights the kinetic challenges for proton transfer to catalytic intermediates in organic media.
