New protic salts of aprotic polar solvents

Favier, Isabelle; Duñach, Élisabet

doi:10.1016/j.tetlet.2004.03.025

Cited by 61 publications

(65 citation statements)

References 11 publications

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“…Nickel powder (SigmaAldrich) and phenylphosphine (Alfa Aesar) were used as received. Dimethylfomamidium triflate, 43 6 ] electrolyte on a Pine Instruments WaveDriver potentiostat with a silver wire pseudoreference separated from the main solution by a glass frit, a glassy carbon counter electrode, and a 3 mm disk glassy carbon working electrode. A freshly polished working electrode was used for every voltammogram recorded.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Potential-Dependent Electrocatalytic Pathways: Controlling Reactivity with pK_a for Mechanistic Investigation of a Nickel-Based Hydrogen Evolution Catalyst

2015

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A detailed mechanistic analysis is presented for the hydrogen evolution catalyst [Ni(P2(Ph)N2(Ph))2(CH2CN)][BF4]2 in acetonitrile (P2(Ph)N2(Ph) = 1,3,5,7-tetraphenyl-1,5-diaza-3,7-diphosphacyclooctane). This complex has a Ni(II/I) redox couple at −0.83 V and a Ni(I/0) redox couple at −1.03 V versus Fc(+/0). These two closely spaced redox events both promote proton reduction catalysis, each via a distinct mechanism: an electrochemical ECEC pathway and an EECC route. The EECC mechanism, operative at more negative potentials, was isolated through use of a weak acid (anilinium, pKa = 10.6 in CH3CN) to avert protonation of the singly reduced species. Electroanalytical methods and time-resolved spectroscopy were used to analyze the kinetics of the elementary steps of hydrogen evolution catalysis. The rate constant for the formation of a nickel(II)–hydride intermediate was determined via measurements of peak shift (k1 = 1.2 × 106 M(-1) s(-1)) and through foot-of-the-wave analysis (k1 = 6.5 × 106 M(-1) s(-1)). Reactivity of the isolated hydride with acid to release hydrogen and regenerate the nickel(II) complex was monitored by stopped-flow spectroscopy. Kinetics obtained from stopped-flow measurements are corroborated by current plateau analysis of the catalytic cyclic voltammograms. These kinetic data suggest the presence of an off-cycle intermediate in the reaction.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Potential-Dependent Electrocatalytic Pathways: Controlling Reactivity with pK_a for Mechanistic Investigation of a Nickel-Based Hydrogen Evolution Catalyst

2015

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“…This acid can be isolated as a crystalline solid [40] and has a pK a of 6.1 in acetonitrile. [41] Turnover frequencies found for H 2 production with H-DMF + were fastest (740 s -1 ) for R = Br and slower (590 s -1 ) for R = H. A slower rate (310 s -1 ) was found for R = OMe, and this is attributed to a lower driving force for elimination of H 2 .…”

Section: Ni Catalysts For Production Of H 2 By Proton Reductionmentioning

confidence: 99%

Molecular Electrocatalysts for the Oxidation of Hydrogen and the Production of Hydrogen – The Role of Pendant Amines as Proton Relays

2011

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Electrocatalysts for efficient conversion between electricity and chemical bonds will play a vital role in future systems for storage and delivery of energy. Our research on functional models of hydrogenase enzymes uses nickel and cobalt, abundant and inexpensive metals, in contrast to platinum, a precious metal used in fuel cells. A key feature of our research is a focus on the use of pendant amines incorporated into diphosphane ligands. These pendant amines function as proton relays, lowering the barrier to proton transfers to and

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“…N, N dimethylformamide is a polar (hydrophilic) aprotic solvent with a high boiling point (156 °C) [18]. In the solvothermal process, a nucleophilic SN 2 attack by DMF can activate elemental selenium to form Se 2-ions [19].…”

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of CuInSe2 nanoparticles elaborated by novel solvothermal protocol using DMF as a solvent

Marai

Djessas

Ayadi

et al. 2015

Journal of Alloys and Compounds

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New protic salts of aprotic polar solvents

Cited by 61 publications

References 11 publications

Potential-Dependent Electrocatalytic Pathways: Controlling Reactivity with pK_a for Mechanistic Investigation of a Nickel-Based Hydrogen Evolution Catalyst

Potential-Dependent Electrocatalytic Pathways: Controlling Reactivity with pK_a for Mechanistic Investigation of a Nickel-Based Hydrogen Evolution Catalyst

Molecular Electrocatalysts for the Oxidation of Hydrogen and the Production of Hydrogen – The Role of Pendant Amines as Proton Relays

Preparation and characterization of CuInSe2 nanoparticles elaborated by novel solvothermal protocol using DMF as a solvent

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New protic salts of aprotic polar solvents

Cited by 61 publications

References 11 publications

Potential-Dependent Electrocatalytic Pathways: Controlling Reactivity with pKa for Mechanistic Investigation of a Nickel-Based Hydrogen Evolution Catalyst

Potential-Dependent Electrocatalytic Pathways: Controlling Reactivity with pKa for Mechanistic Investigation of a Nickel-Based Hydrogen Evolution Catalyst

Molecular Electrocatalysts for the Oxidation of Hydrogen and the Production of Hydrogen – The Role of Pendant Amines as Proton Relays

Preparation and characterization of CuInSe2 nanoparticles elaborated by novel solvothermal protocol using DMF as a solvent

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Resources

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Potential-Dependent Electrocatalytic Pathways: Controlling Reactivity with pK_a for Mechanistic Investigation of a Nickel-Based Hydrogen Evolution Catalyst

Potential-Dependent Electrocatalytic Pathways: Controlling Reactivity with pK_a for Mechanistic Investigation of a Nickel-Based Hydrogen Evolution Catalyst