Activation of proton by the two-electron reduction of a di-iron organometallic complex

Capon, Jean‐François; Gloaguen, Frédéric; Schollhammer, Philippe; Talarmin, Jean

doi:10.1016/j.jelechem.2006.06.005

Cited by 124 publications

(155 citation statements)

References 29 publications

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“…From these results and on the basis of literature precedents [28,29] As shown in Fig. 2, a plot of the ratio of the catalytic current (I cat ) to the peak current , where it reaches a maximum value of I cat /I p = 4.8 (Fig.…”

Section: And Cpe Experiments In the Presence Of P-toluenesulfonic mentioning

confidence: 66%

“…Diiron-dithiolate compounds of the type [Fe 2 (µ-SRS)(CO) 6-x L x ] (R = organic group, L = electron-donor ligand, x ≤ 4) have been shown to electrocatalyze the reduction of acid in organic solvents [19][20][21] and, very recently, in aqueous micellar solutions [22,23](for examples of photo-driven H 2 -production by diiron-dithiolate compounds see [24,25]). The electrocatalytic pathway entails successive electron and proton transfers in a sequence that depends on the nature of the terminal ligand L and the strength of the acid used as proton source [16,26] We [27][28][29][30][31][32], and others [33][34][35][36][37] [27,28].…”

Section: Introductionmentioning

confidence: 99%

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Kinetic and thermodynamic aspects of the electrocatalysis of acid reduction in organic solvent using molecular diiron-dithiolate compounds

Quentel

Gloaguen

2013

Electrochimica Acta

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To cite this version:Francois Quentel, Frederic Gloaguen. Kinetic and thermodynamic aspects of the electrocatalysis of acid reduction in organic solvent using molecular diiron-dithiolate compounds. 2015. AbstractIn an attempt to obtain molecular H 2 production electrocatalysts achieving balanced basicity and reduction potential, we focused on the mono-substituted diiron-dithiolate derivative [Fe 2 (µ-bdt)(CO) 5 (P(OMe) 3 )] (bdt = benzenedithiolate). The electrocatalytic efficiency of this iron-iron hydrogenase model was determined by cyclic voltammetry in acetonitrile using ptoluenesulfonic acid as a proton source. Detailed analysis of the current -potential responses and comparison with the all-CO diiron-dithiolate parent compound clearly show that the effect of the chemical properties on the electrocatalytic efficiency is not fully determined by the turnover frequency under pseudo-first-order approximation and the overpotential defined as the difference between the reduction potential of the electrocatalysts in the absence of acid and the reversible potential of the couple H 2 /acid.

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Section: And Cpe Experiments In the Presence Of P-toluenesulfonic mentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Kinetic and thermodynamic aspects of the electrocatalysis of acid reduction in organic solvent using molecular diiron-dithiolate compounds

Quentel

Gloaguen

2013

Electrochimica Acta

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“…This transient species is a key intermediate in the electro-and photocatalytic H 2 production by iron-thiolate complexes. [41,46] In a previous study, we have shown that proton-reduction electrocatalysis by complex 1 was almost suppressed at pH > 6, [43] suggesting that protonation of the reduced form of complex 1 was slow or hindered at these pH values. The observation of photocatalytic H 2 production at pH 10.5 in aqueous Et 3 N solutions is, therefore, puzzling.…”

Section: Resultsmentioning

confidence: 89%

“…[37][38][39] This approach has been well illustrated by [Fe 2 (m-bdt)(CO) 6 ] (1; bdt = benzenedithiolate; Scheme 1), which is an easily synthesized proton-reduction catalyst combining reversible reductive electrochemistry and good activity at mild potentials in organic solvents: E 1/2 = À1.30 V versus ferrocenium/ferrocene (Fc + /0 ) in MeCN. [40][41][42] Recently, we have demonstrated that complex 1 was still reduced at mild potentials in aqueous solutions [E 1/ Encouraged by these results, we reasoned that complex 1 included in SDS micelles could potentially be an efficient protonreduction catalyst for photocatalytic H 2 production in water. Herein we report the performance of a PGM-free system consisting of complex 1, EY 2À as a sensitizer, and triethylamine (Et 3 N) as a sacrificial electron donor in an aqueous SDS solution.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Hydrogen Production Using Models of the Iron–Iron Hydrogenase Active Site Dispersed in Micellar Solution

2013

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International audienceIron–thiolate complexes of the type [Fe2(μ-bdt)(CO)6−xP(OMe3)x] (bdt=S2C6H4=benzenedithiolate, x≤2) are simplified models of iron–iron hydrogenase enzymes. Recently, we have shown that these water-insoluble organometallic complexes, when included into micelles formed by sodium dodecyl sulfate (SDS), are good catalysts for the electrochemical production of hydrogen in aqueous solutions at pH<6. We herein report that the all-CO derivative [Fe2(μ-bdt)(CO)6] (1), owing to its comparatively low reduction potential, is also a robust molecular catalyst for visible-light-driven production of H2 in aqueous SDS solutions at pH 10.5. Irradiation at λ=455 nm of a system consisting of complex 1, Eosin Y as a sensitizer, and triethylamine as an electron donor produced up to 0.86 mL of H2 in 4.5 h, corresponding to a turnover number of 117 mol of H2 per mol of catalyst. In the presence of a large excess of sensitizer, the production of H2 lasted for more than 30 h, stressing the relative stability of complex 1 under the photocatalytic conditions used herein. Thermodynamic considerations and UV/Vis spectroscopy experiments suggest that the catalytic cycle begins with the photo-driven reduction of complex 1. The reduced intermediate reacts with a proton source to yield iron hydride. Subsequent reduction and protonation steps produce H2, regenerating the starting complex. As a result, the iron–thiolate complex 1 is a versatile proton reduction catalyst that can utilize either solar or electrical energy inputs, providing a starting point for the construction of noble metal-free molecular systems for renewable H2 production

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“…Dithiolate-bridged diiron complexes of the type [Fe 2 (CO) 6 -(l-dithiolate)] have been intensely studied [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] due to their structural resemblance with the two-iron unit of the H-cluster active site of [FeFe]-hydrogenases, enzymes that catalyse the reversible interconversion of protons-electrons and hydrogen. A key step in electrocatalytic proton reduction is protonation of the diiron centre, but [Fe 2 (CO) 6 (l-dithiolate)] complexes are not basic enough to undergo protonation except by extremely strong acids [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

A comparative study of the electrochemical and proton-reduction behaviour of diphosphine-dithiolate complexes [M2(CO)4(μ-dppm){μ-S(CH2) n S}] (M = Fe, Ru; n = 2, 3)

2017

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A comparative study of the electrochemical and proton-reduction behaviour of diphosphine-dithiolate complexes [M 2 (CO) 4 (l-dppm){l-S(CH 2 ) n S}] (M 5 Fe, Ru; n 5 2, 3) -diphosphine)(l-dithiolate)]. Consequently a large number of diphosphine-bridged diiron-dithiolate complexes have been reported [23][24][25][26][27][28][29][30][31][32] but surprisingly little attention has been paid to their proton-reduction chemistry [27-32] even though some, for example [Fe 2 (CO) 4 (l-dppf)(l-pdt)] (dppf = 1,1 0 -bis(diphenylphosphino)ferrocene), have been shown to be efficient proton-reduction catalysts [29]. Similarly, given the large number of diiron complexes tested as proton-reduction catalysts, related diruthenium complexes have not been widely studied [53][54][55][56]. Herein we detail a comparative investigation of the electrochemistry and proton-reduction behaviour of diiron and diruthenium complexes [M 2 (CO) 4 (ldppm)(l-pdt)] [24,27,57] and [M 2 (CO) 4 (l-dppm)(l-edt)] [26,27,57] (Fig. 1). ExperimentalComplexes 1-4 were prepared according to published methods [24,26,27,57] (see ESI for details). IR spectra were recorded on a Nicolet 6700 FT-IR spectrometer in a solution cell fitted with calcium fluoride plates, subtraction Electronic supplementary material The online version of this article

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Activation of proton by the two-electron reduction of a di-iron organometallic complex

Cited by 124 publications

References 29 publications

Kinetic and thermodynamic aspects of the electrocatalysis of acid reduction in organic solvent using molecular diiron-dithiolate compounds

Kinetic and thermodynamic aspects of the electrocatalysis of acid reduction in organic solvent using molecular diiron-dithiolate compounds

Photocatalytic Hydrogen Production Using Models of the Iron–Iron Hydrogenase Active Site Dispersed in Micellar Solution

A comparative study of the electrochemical and proton-reduction behaviour of diphosphine-dithiolate complexes [M2(CO)4(μ-dppm){μ-S(CH2) n S}] (M = Fe, Ru; n = 2, 3)

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