12125-80-3Relevant academic research and scientific papers
Proton-coupled oxygen reduction at liquid-liquid interfaces catalyzed by cobalt porphine
Hatay, Imren,Su, Bin,Li, Fei,Mendez, Manuel Alejandro,Khoury, Tony,Gros, Claude P.,Barbe, Jean-Michel,Ersoz, Mustafa,Samec, Zdenek,Girault, Hubert H.
, p. 13453 - 13459 (2009)
Cobalt porphine (CoP) dissolved in the organic phase of a biphasic system is used to catalyze O2 reduction by an electron donor, ferrocene (Fc). Using voltammetry at the interface between two immiscible electrolyte solutions (ITIES), it is poss
Oxidation kinetics of ferrocene derivatives with dibenzoyl peroxide
Halstead, Joshua M.,Abu-Saleh, Refaat,Schildcrout, Steven M.,Masnovi, John
, p. 39 - 46 (2019)
Chemical oxidation of ferrocene and related derivatives by dibenzoyl peroxide in acetonitrile solution produces ferrocenium and benzoic acid after acidification. The rate law is first order in oxidant and in reductant. Steric effects and activation parameters are consistent with a rate-controlling outer-sphere single-electron transfer (ET) step, and reorganization energies are obtained using Marcus theory with B3LYP calculations. Energetics, optimized structures, and solvent effects indicate that rate is affected more by anion than cation solvation and that oxidation of decamethylferrocene by 3-chloroperoxybenzoic acid does not occur by ET.
Evidence for a Single-Electron-Transfer Activation in the Cleavage of Cobalt-Carbon Bonds of Alkylcobalt(III) Complexes with Iodine
Fukuzumi, Shunichi,Ishikawa, Kunio,Tanaka, Toshio
, p. 1801 - 1804 (1986)
Evidence for a single-electron-transfer (SET) activation in the cleavage of cobalt-carbon bonds of alkylcobalt(III) complexes with iodine is shown by the identification of products that could arise only via an SET pathway as well as by the kinetic comparison between the cleavage reaction of alkylcobalt(III) complexes with iodine and the electron-transfer reaction of ferrocene derivatives with iodine in acetonitrile.
Temperature-independent catalytic two-electron reduction of dioxygen by ferrocenes with a copper(II) tris[2-(2-pyridyl)ethyl]amine catalyst in the presence of perchloric acid
Das, Dipanwita,Lee, Yong-Min,Ohkubo, Kei,Nam, Wonwoo,Karlin, Kenneth D.,Fukuzumi, Shunichi
, p. 2825 - 2834 (2013)
Selective two-electron plus two-proton (2e-/2H+) reduction of O2 to hydrogen peroxide by ferrocene (Fc) or 1,1′-dimethylferrocene (Me2Fc) in the presence of perchloric acid is catalyzed efficiently by a mononuclear copper(II) complex, [Cu II(tepa)]2+ (1; tepa = tris[2-(2-pyridyl)ethyl]amine) in acetone. The E1/2 value for [CuII(tepa)]2+ as measured by cyclic voltammetry is 0.07 V vs Fc/Fc+ in acetone, being significantly positive, which makes it possible to use relatively weak one-electron reductants such as Fc and Me2Fc for the overall two-electron reduction of O2. Fast electron transfer from Fc or Me2Fc to 1 affords the corresponding CuI complex [Cu I(tepa)]+ (2), which reacts at low temperature (193 K) with O2, however only in the presence of HClO4, to afford the hydroperoxo complex [CuII(tepa)(OOH)]+ (3). A detailed kinetic study on the homogeneous catalytic system reveals the rate-determining step to be the O2-binding process in the presence of HClO4 at lower temperature as well as at room temperature. The O2-binding kinetics in the presence of HClO4 were studied, demonstrating that the rate of formation of the hydroperoxo complex 3 as well as the overall catalytic reaction remained virtually the same with changing temperature. The apparent lack of activation energy for the catalytic two-electron reduction of O2 is shown to result from the existence of a pre-equilibrium between 2 and O2 prior to the formation of the hydroperoxo complex 3. No further reduction of [CuII(tepa)(OOH)]+ (3) by Fc or Me2Fc occurred, and instead 3 is protonated by HClO4 to yield H2O2 accompanied by regeneration of 1, thus completing the catalytic cycle for the two-electron reduction of O2 by Fc or Me2Fc.
Mechanism of four-electron reduction of dioxygen to water by ferrocene derivatives in the presence of perchloric acid in benzonitrile, catalyzed by cofacial dicobalt porphyrins
Fukuzumi, Shunichi,Okamoto, Ken,Gros, Claude P.,Guilard, Roger
, p. 10441 - 10449 (2004)
The selective two-electron reduction of dioxygen occurs in the case of a monocobalt porphyrin [Co(OEP)], whereas the selective four-electron reduction of dioxygen occurs in the case of a cofacial dicobalt porphyrin [Co 2(DPX)]. The other cofacial dicobalt porphyrins [Co2(DPA), Co2(DPB), and Co2(DPD)] also catalyze the two-electron reduction of dioxygen, but the four-electron reduction is not as efficient as in the case of Co2(DPX). The μ-superoxo species of cofacial dicobalt porphyrins were produced by the reactions of cofacial dicobalt(II) porphyrins with dioxygen in the presence of a bulky base and the subsequent one-electron oxidation of the resulting μ-peroxo species by iodine. The superhyperfine structure due to two equivalent cobalt nuclei was observed at room temperature in the ESR spectra of the μ-superoxo species. The superhyperfine coupling constant of the μ-superoxo species of Co2(DPX) is the largest among those of cofacial dicobalt porphyrins. This indicates that the efficient catalysis by Co2(DPX) for the four-electron reduction of dioxygen by Fe(C5H4Me)2 results from the strong binding of the reduced oxygen with Co2(DPX) which has a subtle distance between two cobalt nuclei for the oxygen binding. Mechanisms of the catalytic two-electron and four-electron reduction of dioxygen by ferrocene derivatives will be discussed on the basis of detailed kinetics studies on the overall catalytic reactions as well as on each redox reaction in the catalytic cycle. The turnover-determining step in the Co(OEP)-catalyzed two-electron reduction of dioxygen is an electron transfer from ferrocene derivatives to Co(OEP) +, whereas the turnover-determining step in the Co 2(DPX)-catalyzed four-electron reduction of dioxygen changes from the electron transfer to the O-O bond cleavage of the peroxo species of Co 2(DPX), depending on the electron donor ability of ferrocene derivatives.
Fine tuning of the catalytic effect of a metal-free porphyrin on the homogeneous oxygen reduction
Trojanek, Antonin,Langmaier, Jan,Ebera, Jakub,Zali, Stanislav,Barbe, Jean-Michel,Girault, Hubert H.,Samec, Zdenk
, p. 5446 - 5448 (2011)
The catalytic effect of tetraphenylporphyrin on the oxygen reduction with ferrocene in 1,2-dichloroethane can be finely tuned by varying the molar ratio of the acid to the catalyst present in the solution. The mechanism involves binding of molecular oxygen to the protonated free porphyrin base, in competition with ion pairing between the protonated base and the acid anion present.
Dinitrogen addition to c-C5H5Fe(+), C6H6Fe(+) and FeO(+) in the gas phase
Baranov, Vladimir I.,Javahery, Glolamreza,Bohme, Diethard K.
, p. 339 - 343 (1995)
Results of an experimental study using the selection-ion flow tube technique are reported for reactions of bare Fe(+) and iron containing FeX(+) cations (X=C6H6 (or B), c-C5H5 (or Cp), O, (Cp)2, B2) with dinitrogen at 294+/-3 K and at a helium buffer-gas pressure of 0.35+/-0.01 Torr. Fe(+), B2Fe(+) and Cp2Fe(+) do not react with dinitrogen. A very slow sequential addition of two N2 molecules was observed with FeO(+). CpFe(+) and BFe(+) reacted without the subsequent addition of a second N2 molecule. These results provide insight into the bonding of N2 as a ligand with Fe as the coordination centre in the gas-phase, and into intrinsic kinetic aspects of dinitrogen addition.
Effects of hydrogen bonding on metal ion-promoted intramolecular electron transfer and photoinduced electron transfer in a ferrocene-quinone dyad with a rigid amide spacer
Fukuzumi, Shunichi,Okamoto, Ken,Yoshida, Yutaka,Imahori, Hiroshi,Araki, Yasuyuki,Ito, Osamu
, p. 1007 - 1013 (2007/10/03)
A ferrocene-quinone dyad (Fc-Q) with a rigid amide spacer and Fc-(Me)Q dyad, in which the amide proton acting as a hydrogen-bonding acceptor is replaced by the methyl group, are employed to examine the effects of hydrogen bonding on both the thermal and the photoinduced electron-transfer reactions. The hydrogen bonding of the semiquinone radical anion with the amide proton in Fc-Q.- produced by the electron-transfer reduction of Fc-Q is indicated by the significant positive shift of the one-electron reduction potential of Fc-Q. The hyperfine coupling constants of Fc-Q.- also indicate the existence of hydrogen bonding, agreeing with those predicted by the density functional calculation. The hydrogen-bonding dynamics in the photoinduced electron transfer from the ferrocene (Fc) to the quinone moiety (Q) in Fc-Q have been successfully detected in the femtosecond laser flash photolysis experiments. Thermal intramolecular electron transfer from Fc to Q in Fc-Q and Fc-(Me)Q also occurs efficiently in the presence of metal ions in acetonitrile at 298 K. The hydrogen bond formed between the semiquinone radical anion and the amide proton in Fc-Q results in remarkable acceleration of the rate of metal ion-promoted electron transfer as compared to the rate of Fc-(Me)Q in which hydrogen bonding is prohibited. The metal ion-promoted electron-transfer rates are well correlated with the binding energies of superoxide ion-metal ion complexes, which are derived from the gzz values of the ESR spectra.
Mechanisms of hydrogen-, oxygen-, and electron-transfer reactions of cumylperoxyl radical
Fukuzumi, Shunichi,Shimoosako, Kanji,Suenobu, Tomoyoshi,Watanabe, Yoshihito
, p. 9074 - 9082 (2007/10/03)
Rates of hydrogen-transfer reactions from a series of para-substituted N,N-dimethylanilines to cumylperoxyl radical and oxygen-transfer reactions from cumylperoxyl radical to a series of sulfides and phosphines have been determined in propionitrile (EtCN) and pentane at low temperatures by use of ESR. The observed rate constants exhibit first-order and second-order dependence with respect to concentrations of N,N-dimethylanilines. This indicates that the hydrogen- and oxygen-transfer reactions proceed via 1:1 charge-transfer (CT) complexes formed between the substrates and cumylperoxyl radical. The primary kinetic isotope effects are determined by comparing the rates of N,N-dimethylanilines and the corresponding N,N-bis(trideuteriomethyl)anilines. The isotope effect profiles are quite different from those reported for the P-450 model oxidation of the same series of substrates. Rates of electron-transfer reactions from ferrocene derivatives to cumylperoxyl radical have also been determined by use of ESR. The catalytic effects of Sc(OTf)3 (OTf = triflate) on the electron-transfer reactions are compared with those of Sc(OTf)3 on the hydrogen- and oxygen-transfer reactions. Such comparison provides strong evidence that the hydrogen- and oxygen- transfer reactions of cumylperoxyl radical proceed via a one-step hydrogen atom and oxygen atom transfer rather than via an electron transfer from substrates to cumylperoxyl radical.
Electron self-exchange, oxidation, and reduction reactions of bis(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline)copper(II/I) and bis(6,6′-dimethyl-2,2′-bipyridine)copper(II/I) couples in acetonitrile: Gated et for the reduction, oxidation, and self-exchan
Koshino, Nobuyoshi,Kuchiyama, Yoshio,Funahashi, Shigenobu,Takagi, Hideo D.
, p. 1498 - 1507 (2007/10/03)
The electron self-exchange rate constant for the Cu(dmbp)22+/+ couple (dmbp = 6,6′-dimethyl-2,2′-bipyridine) was measured in acetonitrile by the NMR method (kex = 5.5 × 103 kg mol-1 s-1, ΔH
