Mechanistic insights into consecutive 2e− and 2H+ reactions of hydrogenase mimic

Wang, Xu‐Zhe; Meng, Shu‐Lin; Liu, Jianguo; Yu, Can; Ye, Chen; Wang, Haixu; Pang, Maofu; Yu, Xin; Wang, Wenguang; Li, Xu‐Bing; Tung, Chen‐Ho; Wu, Li‐Zhu

doi:10.1016/j.chempr.2023.05.010

“…We proposed that for 1 À , the Cu I state can be rapidly protonated by TFA to form Cu III À H. This Cu III À H will be reduced instantly by unreacted Cu I to give Cu II À H, which then undergoes protonation with TFA to afford H 2 and 1. [10,23,[60][61][62] Similarly, the reduction of 2 and 4 with one equivalent of CoCp 2 * gave 2 À (Figure 3c) and 4 À (Figure 3e), respectively. The UV/Vis spectral changes of these reduction steps also displayed well-defined isosbestic points.…”

mentioning

confidence: 79%

“…We proposed that for 1 − , the Cu I state can be rapidly protonated by TFA to form Cu III −H. This Cu III −H will be reduced instantly by unreacted Cu I to give Cu II −H, which then undergoes protonation with TFA to afford H 2 and 1 [10,23,60–62] …”

Section: Figurementioning

confidence: 99%

Switching Electrocatalytic Hydrogen Evolution Pathways through Electronic Tuning of Copper Porphyrins

Peng,

Zhang,

Qin

et al. 2024

Angewandte Chemie

0

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The electronic structure of metal complexes plays key roles in determining their catalytic features. However, controlling electronic structures to regulate reaction mechanisms is of fundamental interest but has been rarely presented. Herein, we report electronic tuning of Cu porphyrins to switch pathways of the hydrogen evolution reaction (HER). Throughcontrollable and regioselective β‐oxidation of Cu porphyrin 1, we synthesized analogues 2‐4 with one or two β‐lactone groups in either a cis or trans configuration. Complexes 1‐4 have the same Cu‐N4 core site but different electronic structures. Although β‐oxidation led to large anodic shifts of reductions, 1‐4 displayed similar HER activities in terms of close overpotentials. With electrochemical, chemical and theoretical results, we show that the catalytically active species switches from a CuI species for 1 to a Cu0 species for 4. This work is thus significant to present mechanism‐controllable HER via electronic tuning of catalysts.

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“…[24,25] Despite their high activity, hydrogenases are too large and complex for sustainable industrial production, [26] thus, enzyme mimics present a viable alternative. [27][28][29][30] Bio-inspired molecular catalysts aim to emulate the high activity of natural biocatalysts and could be more suitable for large-scale production and application. The effectiveness of dinuclear complexes in catalysis is enhanced by the proximity of two metal centers, facilitating multiple interaction sites with protons or water molecules, thus potentially reducing activation energy and accelerating HER.…”

Section: Introductionmentioning

confidence: 99%

Dinuclear Copper Complex for High‐Rate Hydrogen Evolution Under Neutral Aqueous Conditions

Younus,

Emam,

Ahmad

et al. 2024

ChemElectroChem

2

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The development of an efficient and stable electrocatalyst for the hydrogen evolution reaction (HER), based on earth‐abundant components, represents a crucial step toward cost‐effective and environmentally friendly hydrogen production. This study presents the utilization of a dinuclear copper catalyst, denoted as [Cu‐Gly‐SB] (Complex 1), for HER under both aqueous and non‐aqueous conditions. In non‐aqueous settings, the catalyst achieves excellent HER performance, requiring only a 270 mV overpotential when acetic acid is used as the proton donor. Notably, in fully aqueous conditions, complex 1 attains a remarkable current density of 18.8 mA ⋅ cm−2 at −0.7 V vs. RHE in cyclic voltammetry. The kobs value of ≈2.7×104 s−1 in aqueous solution at pH 7.0 further underlines the superior catalytic performance of 1, outperforming most non‐noble‐metal molecular catalysts functioning in fully aqueous solutions. The robust stability of 1 is demonstrated through controlled potential electrolysis (CPE) over a span of 48 hours, achieving an impressive catalytic current of 11.0 mA ⋅ cm−2 at −0.39 V. Moreover, the catalytic current gradually increases with higher reduction potentials, reaching a substantial 100 mA ⋅ cm−2 at an overpotential of 590 mV during CPE >48 hours. Thorough characterizations further confirm the molecular nature of the catalyst.

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Switching Electrocatalytic Hydrogen Evolution Pathways through Electronic Tuning of Copper Porphyrins

Peng,

Zhang,

Qin

et al. 2024

Angew Chem Int Ed

20

0

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The electronic structure of metal complexes plays key roles in determining their catalytic features. However, controlling electronic structures to regulate reaction mechanisms is of fundamental interest but has been rarely presented. Herein, we report electronic tuning of Cu porphyrins to switch pathways of the hydrogen evolution reaction (HER). Throughcontrollable and regioselective β‐oxidation of Cu porphyrin 1, we synthesized analogues 2‐4 with one or two β‐lactone groups in either a cis or trans configuration. Complexes 1‐4 have the same Cu‐N4 core site but different electronic structures. Although β‐oxidation led to large anodic shifts of reductions, 1‐4 displayed similar HER activities in terms of close overpotentials. With electrochemical, chemical and theoretical results, we show that the catalytically active species switches from a CuI species for 1 to a Cu0 species for 4. This work is thus significant to present mechanism‐controllable HER via electronic tuning of catalysts.

show abstract

Mechanistic insights into consecutive 2e− and 2H+ reactions of hydrogenase mimic

Cited by 6 publications

References 65 publications

Switching Electrocatalytic Hydrogen Evolution Pathways through Electronic Tuning of Copper Porphyrins

Switching Electrocatalytic Hydrogen Evolution Pathways through Electronic Tuning of Copper Porphyrins

Dinuclear Copper Complex for High‐Rate Hydrogen Evolution Under Neutral Aqueous Conditions

Switching Electrocatalytic Hydrogen Evolution Pathways through Electronic Tuning of Copper Porphyrins

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