1
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Sun H, Liu X, Li Y, Zhang F, Huang X, Sun C, Huang F. Mechanistic insights of electrocatalytic CO 2 reduction by Mn complexes: synergistic effects of the ligands. Dalton Trans 2024; 53:1663-1672. [PMID: 38168800 DOI: 10.1039/d3dt03453d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The electrocatalytic mechanisms of CO2 reduction catalyzed by pyridine-oxazoline (pyrox)-based Mn catalysts were investigated by DFT calculations. In-depth comparative analyses of pyrox-based and bipyridine-based Mn complexes were carried out. C-OH cleavage is the rate-determining step for both the protonation-first path and the reduction-first path. The free energy of CO2 activation (ΔG1) and the electrons donated by CO ligands in this step are effective descriptors in regulating the C-OH cleavage barrier. The reduction of carboxylate complex 6 (E6) is the potential-determining step for the reduction-first path. Meanwhile, for the protonation-first path, the initial generation (E2) or the regeneration (E8) of active catalyst might be potential-determining. Hirshfeld charge and orbital contribution analysis indicate that E6 is definitely based on the heterocyclic ligand and E2 is related to both the heterocyclic ligand and three CO ligands. Therefore, replacement of the CO ligand by a stronger electron donating ligand can effectively boost the catalytic activity of CO2 reduction without increasing the overpotential in the reduction-first path. This hypothesis is supported by the mechanism calculations of the Mn complex in which the axial CO ligand is replaced by a pyridine or PMe3.
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Affiliation(s)
- Haitao Sun
- Department of Assets and Laboratory Management, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China.
| | - Xueqing Liu
- Department of Assets and Laboratory Management, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China.
| | - Yafeng Li
- Department of Assets and Laboratory Management, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China.
| | - Fang Zhang
- Department of Assets and Laboratory Management, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China.
| | - Xiuxiu Huang
- Department of Assets and Laboratory Management, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China.
| | - Chuanzhi Sun
- Department of Assets and Laboratory Management, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China.
| | - Fang Huang
- Department of Assets and Laboratory Management, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China.
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2
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Barbero A, Rotundo L, Reviglio C, Gobetto R, Sokolova R, Fiedler J, Nervi C. New Spectroelectrochemical Insights into Manganese and Rhenium Bipyridine Complexes as Catalysts for the Electrochemical Reduction of Carbon Dioxide. Molecules 2023; 28:7535. [PMID: 38005257 PMCID: PMC10673266 DOI: 10.3390/molecules28227535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 11/26/2023] Open
Abstract
This study aimed to demonstrate the behavior of different complexes using IR spectroelectrochemistry (SEC), a technique that combines IR spectroscopy with electrochemistry. Four different Mn and Re catalysts for electrochemical CO2 reduction were studied in dry acetonitrile. In the case of Mn(apbpy)(CO)3Br (apbpy = 4(4-aminophenyl)-2,2'-bipyridine), SEC suggested that a very slow catalytic reduction of CO2 also occurs in acetonitrile in the absence of proton donors, but at rather negative potentials. In contrast, the corresponding Re(apbpy)(CO)3Br clearly demonstrated slow catalytic conversion at the first reduction potential. Switching to saturated CO2 solutions in a mixture of acetonitrile and 5% water as a proton donor, the SEC of Mn(apbpy)(CO)3Br displayed a faster catalytic behavior.
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Affiliation(s)
- Alice Barbero
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Torino, Italy
- CIRCC (Interuniversitary Consortium of Chemical Reactivity and Catalysis), Via Celso Ulpiani 27, 70126 Bari, Italy
| | - Laura Rotundo
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Torino, Italy
- Chemistry Division Brookhaven National Laboratory, Upton, NY 11973-5000, USA
| | - Chiara Reviglio
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Torino, Italy
- CIRCC (Interuniversitary Consortium of Chemical Reactivity and Catalysis), Via Celso Ulpiani 27, 70126 Bari, Italy
| | - Roberto Gobetto
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Torino, Italy
- CIRCC (Interuniversitary Consortium of Chemical Reactivity and Catalysis), Via Celso Ulpiani 27, 70126 Bari, Italy
| | - Romana Sokolova
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Jan Fiedler
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Carlo Nervi
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Torino, Italy
- CIRCC (Interuniversitary Consortium of Chemical Reactivity and Catalysis), Via Celso Ulpiani 27, 70126 Bari, Italy
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3
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Singh KK, Gerke CS, Saund SS, Zito AM, Siegler MA, Thoi VS. CO 2 Activation with Manganese Tricarbonyl Complexes through an H-Atom Responsive Benzimidazole Ligand. Chemistry 2023; 29:e202300796. [PMID: 37519094 DOI: 10.1002/chem.202300796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 07/20/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
Herein, we report the synthesis and characterization of two manganese tricarbonyl complexes, MnI (HL)(CO)3 Br (1 a-Br) and MnI (MeL)(CO)3 Br (1 b-Br) (where HL=2-(2'-pyridyl)benzimidazole; MeL=1-methyl-2-(2'-pyridy)benzimidazole) and assayed their electrocatalytic properties for CO2 reduction. A redox-active pyridine benzimidazole ancillary ligand in complex 1 a-Br displayed unique hydrogen atom transfer ability to facilitate electrocatalytic CO2 conversion at a markedly lower reduction potential than that observed for 1 b-Br. Notably, a one-electron reduction of 1 a-Br yields a structurally characterized H-bonded binuclear Mn(I) adduct (2 a') rather than the typically observed Mn(0)-Mn(0) dimer, suggesting a novel method for CO2 activation. Combining advanced electrochemical, spectroscopic, and single crystal X-ray diffraction techniques, we demonstrate the use of an H-atom responsive ligand may reveal an alternative, low-energy pathway for CO2 activation by an earth-abundant metal complex catalyst.
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Affiliation(s)
- Kundan K Singh
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, United States
| | - Carter S Gerke
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, United States
| | - Simran S Saund
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, United States
| | - Alessandra M Zito
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, United States
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, United States
| | - V Sara Thoi
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, United States
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, United States
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4
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Hong W, Luthra M, Jakobsen JB, Madsen MR, Castro AC, Hammershøj HCD, Pedersen SU, Balcells D, Skrydstrup T, Daasbjerg K, Nova A. Exploring the Parameters Controlling Product Selectivity in Electrochemical CO 2 Reduction in Competition with Hydrogen Evolution Employing Manganese Bipyridine Complexes. ACS Catal 2023; 13:3109-3119. [PMID: 36910875 PMCID: PMC9990071 DOI: 10.1021/acscatal.2c05951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/30/2023] [Indexed: 02/18/2023]
Abstract
Selective reduction of CO2 is an efficient solution for producing nonfossil-based chemical feedstocks and simultaneously alleviating the increasing atmospheric concentration of this greenhouse gas. With this aim, molecular electrocatalysts are being extensively studied, although selectivity remains an issue. In this work, a combined experimental-computational study explores how the molecular structure of Mn-based complexes determines the dominant product in the reduction of CO2 to HCOOH, CO, and H2. In contrast to previous Mn(bpy-R)(CO)3Br catalysts containing alkyl amines in the vicinity of the Br ligand, here, we report that bpy-based macrocycles locking these amines at the side opposite to the Br ligand change the product selectivity from HCOOH to H2. Ab initio molecular dynamics simulations of the active species showed that free rotation of the Mn(CO)3 moiety allows for the approach of the protonated amine to the reactive center yielding a Mn-hydride intermediate, which is the key in the formation of H2 and HCOOH. Additional studies with DFT methods showed that the macrocyclic moiety hinders the insertion of CO2 to the metal hydride favoring the formation of H2 over HCOOH. Further, our results suggest that the minor CO product observed experimentally is formed when CO2 adds to Mn on the side opposite to the amine ligand before protonation. These results show how product selectivity can be modulated by ligand design in Mn-based catalysts, providing atomistic details that can be leveraged in the development of a fully selective system.
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Affiliation(s)
- Wanwan Hong
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Mahika Luthra
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, 0315 Oslo, Norway
| | - Joakim B Jakobsen
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Monica R Madsen
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Abril C Castro
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, 0315 Oslo, Norway
| | - Hans Christian D Hammershøj
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Steen U Pedersen
- Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - David Balcells
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, 0315 Oslo, Norway
| | - Troels Skrydstrup
- Carbon Dioxide Activation Center (CADIAC), Novo Nordisk Foundation (NNF) CO2 Research Center, Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Kim Daasbjerg
- Novo Nordisk Foundation (NNF) CO2 Research Center, Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - Ainara Nova
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, 0315 Oslo, Norway.,Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, 0315 Oslo, Norway
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5
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Loke WLJ, Guo W, Sohail M, Bengali AA, Fan WY. Manganese Tricarbonyl Diimine Bromide Complexes as Electrocatalysts for Proton Reduction. Inorg Chem 2022; 61:20699-20708. [DOI: 10.1021/acs.inorgchem.2c03675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Wen Liang James Loke
- Department of Chemistry, National University of Singapore, 3 Science Drive 3,117543, Singapore
| | - Wenzhuo Guo
- Department of Chemistry, National University of Singapore, 3 Science Drive 3,117543, Singapore
| | - Muhammad Sohail
- Department of Chemistry, Texas A&M University at Qatar, Doha23874, Qatar
| | - Ashfaq A. Bengali
- Department of Chemistry, Texas A&M University at Qatar, Doha23874, Qatar
| | - Wai Yip Fan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3,117543, Singapore
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6
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CO2 Electroreduction on Carbon-Based Electrodes Functionalized with Molecular Organometallic Complexes—A Mini Review. Catalysts 2022. [DOI: 10.3390/catal12111448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterogeneous electrochemical CO2 reduction has potential advantages with respect to the homogeneous counterpart due to the easier recovery of products and catalysts, the relatively small amounts of catalyst necessary for efficient electrolysis, the longer lifetime of the catalysts, and the elimination of solubility problems. Unfortunately, several disadvantages are also present, including the difficulty of designing the optimized and best-performing catalysts by the appropriate choice of the ligands as well as a larger heterogeneity in the nature of the catalytic site that introduces differences in the mechanistic pathway and in electrogenerated products. The advantages of homogeneous and heterogeneous systems can be preserved by anchoring intact organometallic molecules on the electrode surface with the aim of increasing the dispersion of active components at a molecular level and facilitating the electron transfer to the electrocatalyst. Electrode functionalization can be obtained by non-covalent or covalent interactions and by direct electropolymerization on the electrode surface. A critical overview covering the very recent literature on CO2 electroreduction by intact organometallic complexes attached to the electrode is summarized herein, and particular attention is given to their catalytic performances. We hope this mini review can provide new insights into the development of more efficient CO2 electrocatalysts for real-life applications.
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7
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Blasczak V, McKinnon M, Suntrup L, Aminudin NA, Reed B, Groysman S, Ertem MZ, Grills DC, Rochford J. Steric and Lewis Basicity Influence of the Second Coordination Sphere on Electrocatalytic CO 2 Reduction by Manganese Bipyridyl Complexes. Inorg Chem 2022; 61:15784-15800. [PMID: 36162397 DOI: 10.1021/acs.inorgchem.2c02586] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study aims to provide a greater insight into the balance between steric (bpy vs (Ph)2bpy vs mes2bpy ligands) and Lewis basic ((Ph)2bpy vs (MeOPh)2bpy vs (MeSPh)2bpy ligands) influence on the efficiencies of the protonation-first vs reduction-first CO2 reduction mechanisms with [MnI(R2bpy)(CO)3(CH3CN)]+ precatalysts, and on their respective transition-state geometries/energies for rate-determining C-OH bond cleavage toward CO evolution. The presence of only modest steric bulk at the 6,6'-diphenyl-2,2'-bipyridyl ((Ph)2bpy) ligand has here allowed unique insight into the mechanism of catalyst activation and CO2 binding by navigating a perfect medium between the nonsterically encumbered bpy-based and the highly sterically encumbered mes2bpy-based precatalysts. Cyclic voltammetry conducted in CO2-saturated electrolyte for the (Ph)2bpy-based precatalyst [2-CH3CN]+ confirms that CO2 binding occurs at the two-electron-reduced activated catalyst [2]- in the absence of an excess proton source, in contrast to prior assumptions that all manganese catalysts require a strong acid for CO2 binding. This observation is supported by computed free energies of the parent-child reaction for [Mn-Mn]0 dimer formation, where increased steric hindrance relative to the bpy-based precatalyst correlates with favorable CO2 binding. A critical balance must be adhered to, however, as the absence of steric bulk in the bpy-based precatalyst [1-CH3CN]+ maintains a lower overpotential than [2-CH3CN]+ at the protonation-first pathway with comparable kinetic performance, whereas an ∼2-fold greater TOFmax is observed at its reduction-first pathway with an almost identical overpotential as [2-CH3CN]+. Notably, excessive steric bulk in the mes2bpy-based precatalyst [3-CH3CN]+ results in increased activation free energies of the C-OH bond cleavage transition states for both the protonation-first and the reduction-first pathways relative to both [1-CH3CN]+ and [2-CH3CN]+. In fact, [3-CH3CN]+ requires a 1 V window beyond its onset potential to reach its peak catalytic current, which is in contrast to the narrower (<0.30 V) potential response window of the remaining catalysts here studied. Voltammetry recorded under 1 atm of CO2 with 2.8 M (5%) H2O establishes [2-CH3CN]+ to have the lowest overpotential (η = 0.75 V) in the series here studied, attributed to its ability to lie "on the fence" when providing sufficient steric bulk to hinder (but not prevent) [Mn-Mn]0 dimerization, while simultaneously having a limited steric impact on the free energy of activation for the rate-determining C-OH bond cleavage transition state. While the methoxyphenyl bpy-based precatalyst [4-CH3CN]+ possesses an increased steric presence relative to [2-CH3CN]+, this is offset by its capacity to stabilize the C-OH bond cleavage transition states of both the protonation-first and the reduction-first pathways by facilitating second coordination sphere H-bonding stabilization.
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Affiliation(s)
- Vanna Blasczak
- Department of Chemistry, University of Massachusetts─Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Meaghan McKinnon
- Department of Chemistry, University of Massachusetts─Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Lisa Suntrup
- Department of Chemistry, University of Massachusetts─Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Nur Alisa Aminudin
- Department of Chemistry, University of Massachusetts─Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Blake Reed
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Stanislav Groysman
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Mehmed Z Ertem
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - David C Grills
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Jonathan Rochford
- Department of Chemistry, University of Massachusetts─Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
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8
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Scherpf T, Carr CR, Donnelly LJ, Dubrawski ZS, Gelfand BS, Piers WE. A Mesoionic Carbene-Pyridine Bidentate Ligand That Improves Stability in Electrocatalytic CO 2 Reduction by a Molecular Manganese Catalyst. Inorg Chem 2022; 61:13644-13656. [PMID: 35981323 DOI: 10.1021/acs.inorgchem.2c02689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tricarbonyl Group 7 complexes have a longstanding history as efficacious CO2 electroreduction catalysts. Typically, these complexes feature an auxiliary 2,2'-bipyridine ligand that assists in redox steps by delocalizing the electron density into the ligand orbitals. While this feature lends to an accessible redox potential for CO2 electroreduction, it also presents challenges for electrocatalysis with Mn because the electron density is removed from metal-ligand bonding orbitals. The results presented here thus introduce a mesoionic carbene (MIC) as a potent ligand platform to promote Mn-based electrocatalysis. The strong σ donation of the N,C-bidentate MIC is shown to help centralize the electron density on the Mn center while also maintaining relevant redox potentials for CO2 electroreduction. Mechanistic investigation supports catalytic turnover at two operative potentials separated by 400 mV. In the low operating potential regime at -1.54 V, Mn(0) species catalyze CO2 to CO and CO32-, which has a maximum rate of 7 ± 5 s-1 and is stable for up to 30.7 h. At higher operating potential at -1.94 V, "Mn(-1)" catalyzes CO2 to CO and H2O with faster turnovers of 200 ± 100 s-1, with the trade-off being less stability at 6.7 h. The relative stabilities of Mn complexes bearing MIC and 4,4'-di-tert-butyl-2,2'-bipyridine were compared by evaluation under the same electrolysis conditions and therefore elucidated that the MIC promotes longevity for CO evolution throughout a 5 h period.
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Affiliation(s)
- Thorsten Scherpf
- Department of Chemistry, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada
| | - Cody R Carr
- Department of Chemistry, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada
| | - Laurie J Donnelly
- Department of Chemistry, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada
| | - Zachary S Dubrawski
- Department of Chemistry, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada
| | - Benjamin S Gelfand
- Department of Chemistry, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada
| | - Warren E Piers
- Department of Chemistry, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada
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9
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Shipp J, Parker S, Spall S, Peralta-Arriaga SL, Robertson CC, Chekulaev D, Portius P, Turega S, Buckley A, Rothman R, Weinstein JA. Photocatalytic Reduction of CO 2 to CO in Aqueous Solution under Red-Light Irradiation by a Zn-Porphyrin-Sensitized Mn(I) Catalyst. Inorg Chem 2022; 61:13281-13292. [PMID: 35960651 PMCID: PMC9446891 DOI: 10.1021/acs.inorgchem.2c00091] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
This work demonstrates photocatalytic CO2 reduction
by a noble-metal-free photosensitizer-catalyst system in aqueous solution
under red-light irradiation. A water-soluble Mn(I) tricarbonyl diimine
complex, [MnBr(4,4′-{Et2O3PCH2}2-2,2′-bipyridyl)(CO)3] (1), has been fully characterized, including single-crystal X-ray crystallography,
and shown to reduce CO2 to CO following photosensitization
by tetra(N-methyl-4-pyridyl)porphyrin Zn(II) tetrachloride
[Zn(TMPyP)]Cl4 (2) under 625 nm irradiation.
This is the first example of 2 employed as a photosensitizer
for CO2 reduction. The incorporation of −P(O)(OEt)2 groups, decoupled from the core of the catalyst by a −CH2– spacer, afforded water solubility without compromising
the electronic properties of the catalyst. The photostability of the
active Mn(I) catalyst over prolonged periods of irradiation with red
light was confirmed by 1H and 13C{1H} NMR spectroscopy. This first report on Mn(I) species as a homogeneous
photocatalyst, working in water and under red light, illustrates further
future prospects of intrinsically photounstable Mn(I) complexes as
solar-driven catalysts in an aqueous environment. A Mn(I) bipyridyl tricarbonyl complex,
where the diimine
ligand is functionalized with water-solubilizing phosphonate ester
groups, has been prepared and is shown to catalytically convert CO2 to CO in aqueous solution following photosensitization from
a water-soluble Zn(II) porphyrin under red-light irradiation.
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Affiliation(s)
- James Shipp
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Simon Parker
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Steven Spall
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | | | - Craig C Robertson
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Dimitri Chekulaev
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Peter Portius
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Simon Turega
- Department of Chemistry, Sheffield Hallam University, Sheffield S1 1WB, U.K
| | - Alastair Buckley
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - Rachael Rothman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, U.K
| | - Julia A Weinstein
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
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10
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Stuardi FM, Tiozzo A, Rotundo L, Leclaire J, Gobetto R, Nervi C. Efficient Electrochemical Reduction of CO 2 to Formate in Methanol Solutions by Mn-Functionalized Electrodes in the Presence of Amines. Chemistry 2022; 28:e202104377. [PMID: 35471768 PMCID: PMC9325359 DOI: 10.1002/chem.202104377] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Indexed: 11/24/2022]
Abstract
Carbon cloth electrode modified by covalently attaching a manganese organometallic catalyst is used as cathode for the electrochemical reduction of CO2 in methanol solutions. Six different industrial amines are employed as co‐catalyst in millimolar concentrations to deliver a series of new reactive system. While such absorbents were so far believed to provide a CO2 reservoir and act as sacrificial proton source, we herein demonstrate that this role can be played by methanol, and that the adduct formed between CO2 and the amine can act as an effector or inhibitor toward the catalyst, thereby enhancing or reducing the production of formate. Pentamethyldiethylentriamine (PMDETA), identified as the best effector in our series, converts CO2 in wet methanolic solution into bisammonium bicarbonate. Computational studies revealed that this adduct is responsible for a barrierless transformation of CO2 to formate by the reduced form of the Mn catalyst covalently bonded to the electrode surface. As a consequence, selectivity can be switched on demand from CO to formate anion, and in the case of (PMDETA) an impressive TONHCOO− of 2.8×104 can be reached. This new valuable knowledge on an integrated capture and utilization system paves the way toward more efficient transformation of CO2 into liquid fuel.
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Affiliation(s)
| | - Arianna Tiozzo
- University of Turin, Department of Chemistry, Via P. Giuria 7, 10125, Turin, Italy.,CIRCC, via Celso Ulpiani 27, 70126, Bari, Italy
| | - Laura Rotundo
- University of Turin, Department of Chemistry, Via P. Giuria 7, 10125, Turin, Italy.,CIRCC, via Celso Ulpiani 27, 70126, Bari, Italy.,current address: Chemistry Division, Brookhaven National Laboratory, Upton, NY 11973-5000, USA
| | - Julien Leclaire
- University of Lyon, CNRS, CPE Lyon, INSA, ICBMS UMR 5246, 69611, Lyon, France
| | - Roberto Gobetto
- University of Turin, Department of Chemistry, Via P. Giuria 7, 10125, Turin, Italy.,CIRCC, via Celso Ulpiani 27, 70126, Bari, Italy
| | - Carlo Nervi
- University of Turin, Department of Chemistry, Via P. Giuria 7, 10125, Turin, Italy.,CIRCC, via Celso Ulpiani 27, 70126, Bari, Italy
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11
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Fujita E, Grills DC, Manbeck GF, Polyansky DE. Understanding the Role of Inter- and Intramolecular Promoters in Electro- and Photochemical CO 2 Reduction Using Mn, Re, and Ru Catalysts. Acc Chem Res 2022; 55:616-628. [PMID: 35133133 DOI: 10.1021/acs.accounts.1c00616] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recycling of carbon dioxide to fuels and chemicals is a promising strategy for renewable energy storage. Carbon dioxide conversion can be achieved by (i) artificial photosynthesis using photoinduced electrons; (ii) electrolysis using electricity produced by photovoltaics; and (iii) thermal CO2 hydrogenation using renewable H2. The focus of our group's research is on molecular catalysts, in particular coordination complexes of transition metals (e.g., Mn, Re, and Ru), which offer versatile platforms for mechanistic studies of photo- and electrochemical CO2 reduction. The interactions of catalytic intermediates with Lewis or Brønsted acids, hydrogen-bonding moieties, solvents, cations, etc., that function as promoters or cofactors have become increasingly important for efficient catalysis. These interactions may have dramatic effects on selectivity and rates by stabilizing intermediates or lowering transition state barriers, but they are difficult to elucidate and challenging to predict. We have been carrying out experimental and theoretical studies of CO2 reduction using molecular catalysts toward addressing mechanisms of efficient CO2 reduction systems with emphasis on those containing intramolecular (or pendent) and intermolecular (solution phase) additives. This Account describes the identification of reaction intermediates produced during CO2 reduction in the presence of triethanolamine or ionic liquids, the benefits of hydrogen-bonding interactions among intermediates or cofactors, and the complications of pendent phenolic donors/phenoxide bases under electrochemical conditions.Triethanolamine (TEOA) is a common sacrificial electron donor for photosensitizer excited state reductive quenching and has a long history of use in photocatalytic CO2 reduction. It also functions as a Brønsted base in conjunction with more potent sacrificial electron donors, such as 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH). Deprotonation of the BIH•+ cation radical promotes irreversible photoinduced electron transfer by preventing charge recombination. Despite its wide use, most research to date has not considered the broader reactions of TEOA, including its direct interaction with CO2 or its influence on catalytic intermediates. We found that in acetonitrile, TEOA captures CO2 in the form of a zwitterionic adduct without any metal catalyst. In the presence of ruthenium carbonyl catalysts bearing α-diimine ligands, it participates in metal hydride formation, accelerates hydride transfer to CO2 to form the bound formate intermediate, and assists in the dissociation of formate anion from the catalyst ( J. Am. Chem. Soc. 2020, 142, 2413-2428).Hydrogen bonding and acid/base promoters are understood to interact with key catalytic intermediates, such as the metallocarboxylate or metallocarboxylic acid during CO2 reduction. The former is a high energy species, and hydrogen-bonding or Lewis acid-stabilization are beneficial. We have found that imidazolium-based ionic liquid cations can stabilize the doubly reduced form of the [ReCl(bpy)(CO)3] (bpy = 2,2'-bipyridine) electrocatalyst through both hydrogen-bonding and π-π interactions, resulting in CO2 reduction occurring at a more positive potential with a higher catalytic current ( J. Phys. Chem. Lett. 2014, 5, 2033-2038). Hydrogen bonding interactions between Lewis basic methoxy groups in the second coordination sphere of a Mn-based catalyst and the OH group of the Mn-COOH intermediate in the presence of a Brønsted acid were also found to promote C-(OH) bond cleavage, enabling access to a low-energy protonation-first pathway for CO2 reduction ( J. Am. Chem. Soc. 2017, 139, 2604-2618).The kinetics of forming the metallocarboxylic acid can be enhanced by internal acids, and its proton-induced C-OH bond cleavage to the metallocarbonyl and H2O is often the rate-limiting step. Therefore, proton movement organized by pendent hydrogen-bonding networks may also accelerate this step. In contrast, during electrolysis, OH groups in the second coordination sphere are deprotonated to the oxyanions, which deter catalytic CO2 reduction by directly binding CO2 to form the carbonate or by making an M-O bond in competition with CO2 binding ( Inorg. Chem. 2016, 55, 4582-4594). Our results emphasize that detailed mechanistic research is critical in discovering the design principles for improved catalysts.
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Affiliation(s)
- Etsuko Fujita
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - David C. Grills
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Gerald F. Manbeck
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Dmitry E. Polyansky
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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Madsen MR, Rønne MH, Heuschen M, Golo D, Ahlquist MSG, Skrydstrup T, Pedersen SU, Daasbjerg K. Promoting Selective Generation of Formic Acid from CO 2 Using Mn(bpy)(CO) 3Br as Electrocatalyst and Triethylamine/Isopropanol as Additives. J Am Chem Soc 2021; 143:20491-20500. [PMID: 34813304 DOI: 10.1021/jacs.1c10805] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Urgent solutions are needed to efficiently convert the greenhouse gas CO2 into higher-value products. In this work, fac-Mn(bpy)(CO)3Br (bpy = 2,2'-bipyridine) is employed as electrocatalyst in reductive CO2 conversion. It is shown that product selectivity can be shifted from CO toward HCOOH using appropriate additives, i.e., Et3N along with iPrOH. A crucial aspect of the strategy is to outrun the dimer-generating parent-child reaction involving fac-Mn(bpy)(CO)3Br and [Mn(bpy)(CO)3]- and instead produce the Mn hydride intermediate. Preferentially, this is done at the first reduction wave to enable formation of HCOOH at an overpotential as low as 260 mV and with faradaic efficiency of 59 ± 1%. The latter may be increased to 71 ± 3% at an overpotential of 560 mV, using 2 M concentrations of both Et3N and iPrOH. The nature of the amine additive is crucial for product selectivity, as the faradaic efficiency for HCOOH formation decreases to 13 ± 4% if Et3N is replaced with Et2NH. The origin of this difference lies in the ability of Et3N/iPrOH to establish an equilibrium solution of isopropyl carbonate and CO2, while with Et2NH/iPrOH, formation of the diethylcarbamic acid is favored. According to density-functional theory calculations, CO2 in the former case can take part favorably in the catalytic cycle, while this is less opportune in the latter case because of the CO2-to-carbamic acid conversion. This work presents a straightforward procedure for electrochemical reduction of CO2 to HCOOH by combining an easily synthesized manganese catalyst with commercially available additives.
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Affiliation(s)
- Monica R Madsen
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Magnus H Rønne
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Marvin Heuschen
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Dusanka Golo
- Department of Theoretical Chemistry & Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 10691 Stockholm, Sweden
| | - Mårten S G Ahlquist
- Department of Theoretical Chemistry & Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 10691 Stockholm, Sweden
| | - Troels Skrydstrup
- Carbon Dioxide Activation Center (CADIAC), Interdisciplinary Nanoscience Center, Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Steen U Pedersen
- Department of Chemistry, Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Kim Daasbjerg
- Department of Chemistry, Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
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Deeba R, Chardon-Noblat S, Costentin C. Homogeneous molecular catalysis of the electrochemical reduction of N 2O to N 2: redox vs. chemical catalysis. Chem Sci 2021; 12:12726-12732. [PMID: 34703559 PMCID: PMC8494024 DOI: 10.1039/d1sc03044b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 08/24/2021] [Indexed: 12/20/2022] Open
Abstract
Homogeneous electrochemical catalysis of N2O reduction to N2 is investigated with a series of organic catalysts and rhenium and manganese bipyridyl carbonyl complexes. An activation-driving force correlation is revealed with the organic species characteristic of a redox catalysis involving an outer-sphere electron transfer from the radical anions or dianions of the reduced catalyst to N2O. Taking into account the previously estimated reorganization energy required to form the N2O radical anions leads to an estimation of the N2O/N2O˙− standard potential in acetonitrile electrolyte. The direct reduction of N2O at a glassy carbon electrode follows the same quadratic activation driving force relationship. Our analysis reveals that the catalytic effect of the mediators is due to a smaller reorganization energy of the homogeneous electron transfer than that of the heterogeneous one. The physical effect of “spreading” electrons in the electrolyte is shown to be unfavorable for the homogeneous reduction. Importantly, we show that the reduction of N2O by low valent rhenium and manganese bipyridyl carbonyl complexes is of a chemical nature, with an initial one-electron reduction process associated with a chemical reaction more efficient than the simple outer-sphere electron transfer process. This points to an inner-sphere mechanism possibly involving partial charge transfer from the low valent metal to the binding N2O and emphasizes the differences between chemical and redox catalytic processes. Homogeneous electrochemical catalysis of N2O reduction to N2 is investigated with a series of organic catalysts and rhenium and manganese bipyridyl carbonyl complexes.![]()
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Affiliation(s)
- Rana Deeba
- Univ Grenoble Alpes, DCM, CNRS 38000 Grenoble France
| | | | - Cyrille Costentin
- Univ Grenoble Alpes, DCM, CNRS 38000 Grenoble France .,Université de Paris 75013 Paris France
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