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White NM, Waldie KM. Electrocatalytic formate and alcohol oxidation by hydride transfer at first-row transition metal complexes. Dalton Trans 2024; 53:11644-11654. [PMID: 38896286 DOI: 10.1039/d3dt04304e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
The electrocatalytic oxidation of carbon-based liquid fuels, such as formic acid and alcohols, has important applications for our renewable energy transition. Molecular electrocatalysts based on transition metal complexes provide the opportunity to explore the interplay between precise catalyst design and electrocatalytic activity. Recent advances have seen the development of first-row transition metal electrocatalysts for these transformations that operate via hydride transfer between the substrate and catalyst. In this Frontier article, we present the key contributions to this field and discuss the proposed mechanisms for each case. These studies also reveal the remaining challenges for formate and alcohol oxidation with first-row transition metal systems, for which we provide perspectives on future directions for next-generation electrocatalyst design.
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Affiliation(s)
- Navar M White
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, New Jersey 08854, USA.
| | - Kate M Waldie
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, New Jersey 08854, USA.
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2
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Lee Y, Choi M, Bae S, Tayal A, Seo O, Lim H, Lee KS, Jang JH, Jeong B, Lee J. Snowflake relocated Cu 2O electrocatalyst on an Ag backbone template for the production of liquid C 2+ chemicals from CO 2. Dalton Trans 2024; 53:8328-8334. [PMID: 38666327 DOI: 10.1039/d4dt00199k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2024]
Abstract
In this study, we performed the CO2 reduction reaction (CO2RR) using a structural composite catalyst of cuprous oxide (Cu2O) and silver (Ag) that was simultaneously electrodeposited. While the underneath Ag electrodeposits maintained their spiky backbone structures even after the CO2RR, the Cu2O deposits were reduced to Cu(111) and relocated on the backbone template. The structural changes in Cu2O to Cu increase the active area of the Cu-Ag interface, resulting in a remarkable production rate of 125.01 μmol h-1 of liquid C2+ chemicals via the stabilization of the C-C coupling of the key intermediate species of acetaldehyde. This study provides new insights into designing a bimetallic catalyst for producing sustainable C2+ products from CO2 without any selectivity towards the production of methane.
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Affiliation(s)
- Youjin Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea.
- International Future Research Center of Chemical Energy Storage and Conversion Processes (ifRC-CHESS), GIST, 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea
- Ertl Center for Electrochemistry and Catalysis, GIST, 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Minjun Choi
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea.
- International Future Research Center of Chemical Energy Storage and Conversion Processes (ifRC-CHESS), GIST, 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea
- Ertl Center for Electrochemistry and Catalysis, GIST, 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Sooan Bae
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea.
- International Future Research Center of Chemical Energy Storage and Conversion Processes (ifRC-CHESS), GIST, 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea
- Ertl Center for Electrochemistry and Catalysis, GIST, 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Akhil Tayal
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Okkyun Seo
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | - Hojoon Lim
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Kug-Seung Lee
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jae Hyuck Jang
- Center for Research Equipment, Korea Basic Science Institute (KBSI), 169-148 Gwahak-ro, Yuseong-gu, Daejeon 34133, Republic of Korea
| | - Beomgyun Jeong
- Research Center for Materials Analysis, KBSI, 169-148 Gwahak-ro, Yuseong-gu, Daejeon 34133, Republic of Korea.
| | - Jaeyoung Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea.
- International Future Research Center of Chemical Energy Storage and Conversion Processes (ifRC-CHESS), GIST, 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea
- Ertl Center for Electrochemistry and Catalysis, GIST, 123 Cheomdangwagi-Ro, Buk-gu, Gwangju 61005, Republic of Korea
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3
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Cloward IN, Liu T, Rose J, Jurado T, Bonn AG, Chambers MB, Pitman CL, Ter Horst MA, Miller AJM. Catalyst self-assembly accelerates bimetallic light-driven electrocatalytic H 2 evolution in water. Nat Chem 2024; 16:709-716. [PMID: 38528106 DOI: 10.1038/s41557-024-01483-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 02/21/2024] [Indexed: 03/27/2024]
Abstract
Hydrogen evolution is an important fuel-generating reaction that has been subject to mechanistic debate about the roles of monometallic and bimetallic pathways. The molecular iridium catalysts in this study undergo photoelectrochemical dihydrogen (H2) evolution via a bimolecular mechanism, providing an opportunity to understand the factors that promote bimetallic H-H coupling. Covalently tethered diiridium catalysts evolve H2 from neutral water faster than monometallic catalysts, even at lower overpotential. The unexpected origin of this improvement is non-covalent supramolecular self-assembly into nanoscale aggregates that efficiently harvest light and form H-H bonds. Monometallic catalysts containing long-chain alkane substituents leverage the self-assembly to evolve H2 from neutral water at low overpotential and with rates close to the expected maximum for this light-driven water splitting reaction. Design parameters for holding multiple catalytic sites in close proximity and tuning catalyst microenvironments emerge from this work.
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Affiliation(s)
- Isaac N Cloward
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tianfei Liu
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin, China
| | - Jamie Rose
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tamara Jurado
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Annabell G Bonn
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Matthew B Chambers
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Catherine L Pitman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Marc A Ter Horst
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Alexander J M Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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4
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Nishiori D, Menzel JP, Armada N, Reyes Cruz EA, Nannenga BL, Batista VS, Moore GF. Breaking a Molecular Scaling Relationship Using an Iron-Iron Fused Porphyrin Electrocatalyst for Oxygen Reduction. J Am Chem Soc 2024; 146:11622-11633. [PMID: 38639470 DOI: 10.1021/jacs.3c08586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
The design of efficient electrocatalysts is limited by scaling relationships governing trade-offs between thermodynamic and kinetic performance metrics. This ″iron law″ of electrocatalysis arises from synthetic design strategies, where structural alterations to a catalyst must balance nucleophilic versus electrophilic character. Efforts to circumvent this fundamental impasse have focused on bioinspired applications of extended coordination spheres and charged sites proximal to a catalytic center. Herein, we report evidence for breaking a molecular scaling relationship involving electrocatalysis of the oxygen reduction reaction (ORR) by leveraging ligand design. We achieve this using a binuclear catalyst (a diiron porphyrin), featuring a macrocyclic ligand with extended electronic conjugation. This ligand motif delocalizes electrons across the molecular scaffold, improving the catalyst's nucleophilic and electrophilic character. As a result, our binuclear catalyst exhibits low overpotential and high catalytic turnover frequency, breaking the traditional trade-off between these two metrics.
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Affiliation(s)
- Daiki Nishiori
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
- Center for Applied Structural Discovery (CASD), The Biodesign Institute, Arizona State University, Tempe, Arizona 85281, United States
| | - Jan Paul Menzel
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Nicholas Armada
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
- Center for Applied Structural Discovery (CASD), The Biodesign Institute, Arizona State University, Tempe, Arizona 85281, United States
| | - Edgar A Reyes Cruz
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
- Center for Applied Structural Discovery (CASD), The Biodesign Institute, Arizona State University, Tempe, Arizona 85281, United States
| | - Brent L Nannenga
- Center for Applied Structural Discovery (CASD), The Biodesign Institute, Arizona State University, Tempe, Arizona 85281, United States
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Victor S Batista
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Gary F Moore
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
- Center for Applied Structural Discovery (CASD), The Biodesign Institute, Arizona State University, Tempe, Arizona 85281, United States
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5
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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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Jennings M, Cuéllar E, Rojo A, Ferrero S, García-Herbosa G, Nganga J, Angeles-Boza AM, Martín-Alvarez JM, Miguel D, Villafañe F. 1,2-Azolylamidino ruthenium(II) complexes with DMSO ligands: electro- and photocatalysts for CO 2 reduction. Dalton Trans 2023; 52:16974-16983. [PMID: 37933188 DOI: 10.1039/d3dt01122d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
New 1,2-azolylamidino complexes fac-[RuCl(DMSO)3(NHC(R)az*-κ2N,N)]OTf [R = Me (2), Ph (3); az* = pz (pyrazolyl, a), indz (indazolyl, b)] are synthesized via chloride abstraction from their corresponding precursors cis,fac-[RuCl2(DMSO)3(az*H)] (1) after subsequent base-catalyzed coupling of the appropriate nitrile with the 1,2-azole previously coordinated. All the compounds are characterized by 1H NMR, 13C NMR and IR spectroscopy. Those derived from MeCN are also characterized by X-ray diffraction. Electrochemical studies showed several reduction waves in the range of -1.5 to -3 V. The electrochemical behavior in CO2 media is consistent with CO2 electrocatalytic reduction. The catalytic activity expressed as [icat(CO2)/ip(Ar)] ranged from 1.7 to 3.7 for the 1,2-azolylamidino complexes at voltages of ca. -2.7 to -3 V vs. ferrocene/ferrocenium. Controlled potential electrolysis showed rapid decomposition of the Ru catalysts. Photocatalytic CO2 reduction experiments using compounds 1b, 2b and 3b carried out in a CO2-saturated MeCN/TEOA (4 : 1 v/v) solution containing a mixture of the catalyst and [Ru(bipy)3]2+ as the photosensitizer under continuous irradiation (light intensity of 150 mW cm-2 at 25 °C, λ > 300 nm) show that compounds 1b, 2b and 3b allowed CO2 reduction catalysis, producing CO and trace amounts of formate. The combined turnover number for the production of formate and CO is ca. 100 after 8 h and follows the order 1b < 2b ≈ 3b.
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Affiliation(s)
- Murphy Jennings
- Institute of Materials Science, University of Connecticut, 97 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Elena Cuéllar
- GIR MIOMeT-IU Cinquima-Química Inorgánica, Facultad de Ciencias, Campus Miguel Delibes, Universidad de Valladolid, 47011 Valladolid, Spain.
| | - Ariadna Rojo
- GIR MIOMeT-IU Cinquima-Química Inorgánica, Facultad de Ciencias, Campus Miguel Delibes, Universidad de Valladolid, 47011 Valladolid, Spain.
| | - Sergio Ferrero
- GIR MIOMeT-IU Cinquima-Química Inorgánica, Facultad de Ciencias, Campus Miguel Delibes, Universidad de Valladolid, 47011 Valladolid, Spain.
| | - Gabriel García-Herbosa
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, 09001 Burgos, Spain
| | - John Nganga
- Department of Chemistry, University of Connecticut, 55 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Alfredo M Angeles-Boza
- Institute of Materials Science, University of Connecticut, 97 N. Eagleville Rd, Storrs, CT 06269, USA
- Department of Chemistry, University of Connecticut, 55 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Jose M Martín-Alvarez
- GIR MIOMeT-IU Cinquima-Química Inorgánica, Facultad de Ciencias, Campus Miguel Delibes, Universidad de Valladolid, 47011 Valladolid, Spain.
| | - Daniel Miguel
- GIR MIOMeT-IU Cinquima-Química Inorgánica, Facultad de Ciencias, Campus Miguel Delibes, Universidad de Valladolid, 47011 Valladolid, Spain.
| | - Fernando Villafañe
- GIR MIOMeT-IU Cinquima-Química Inorgánica, Facultad de Ciencias, Campus Miguel Delibes, Universidad de Valladolid, 47011 Valladolid, Spain.
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Saha S, Doughty T, Banerjee D, Patel SK, Mallick D, Iyer ESS, Roy S, Mitra R. Electrocatalytic reduction of CO 2 to CO by a series of organometallic Re(I)-tpy complexes. Dalton Trans 2023; 52:15394-15411. [PMID: 37203345 DOI: 10.1039/d3dt00441d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A series of organometallic Re(I)(L)(CO)3Br complexes with 4'-substituted terpyridine ligands (L) has been synthesised as electrocatalysts for CO2 reduction. The complexes' spectroscopic characterisation and computationally optimised geometry demonstrate a facial geometry around Re(I) with three cis COs and the terpyridine ligand coordinating in a bidentate mode. The effect of substitution on the 4'-position of terpyridine (Re1-5) on CO2 electroreduction was investigated and compared with a known Lehn-type catalyst, Re(I)(bpy)(CO)3Br (Re7). All complexes catalyse CO evolution in homogeneous organic media at moderate overpotentials (0.75-0.95 V) with faradaic yields of 62-98%. The electrochemical catalytic activity was further evaluated in the presence of three Brønsted acids to demonstrate the influence of the pKa of the proton sources. The TDDFT and ultrafast transient absorption spectroscopy (TAS) studies showed combined charge transfer bands of ILCT and MLCT. Amongst the series, the Re-complex containing a ferrocenyl-substituted terpyridine ligand (Re5) shows an additional intra-ligand charge transfer band and was probed using UV-Vis spectroelectrochemistry.
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Affiliation(s)
- Shriya Saha
- School of Chemical and Materials Sciences, Indian Institute of Technology Goa, Farmagudi, Goa 403401, India.
| | - Thomas Doughty
- School of Chemistry, University of Lincoln, Green Lane, Lincoln, Lincolnshire, LN6 7DL, UK.
| | - Dibyendu Banerjee
- Department of Chemistry, Presidency University, Kolkata 700073, India.
| | - Sunil K Patel
- School of Chemical and Materials Sciences, Indian Institute of Technology Goa, Farmagudi, Goa 403401, India.
| | - Dibyendu Mallick
- Department of Chemistry, Presidency University, Kolkata 700073, India.
| | - E Siva Subramaniam Iyer
- School of Chemical and Materials Sciences, Indian Institute of Technology Goa, Farmagudi, Goa 403401, India.
| | - Souvik Roy
- School of Chemistry, University of Lincoln, Green Lane, Lincoln, Lincolnshire, LN6 7DL, UK.
| | - Raja Mitra
- School of Chemical and Materials Sciences, Indian Institute of Technology Goa, Farmagudi, Goa 403401, India.
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Kim K, Wagner P, Wagner K, Mozer AJ. Effect of the Cu 2+/1+ Redox Potential of Non-Macrocyclic Cu Complexes on Electrochemical CO 2 Reduction. Molecules 2023; 28:5179. [PMID: 37446840 DOI: 10.3390/molecules28135179] [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: 06/09/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
Cu2+/1+ complexes facilitate the reduction of CO2 to valuable chemicals. The catalytic conversion likely involves the binding of CO2 and/or reduction intermediates to Cu2+/1+, which in turn could be influenced by the electron density on the Cu2+/1+ ion. Herein we investigated whether modulating the redox potential of Cu2+/1+ complexes by changing their ligand structures influenced their CO2 reduction performance significantly. We synthesised new heteroleptic Cu2/1+ complexes, and for the first time, studied a (Cu-bis(8-quinolinolato) complex, covering a Cu2+/1+ redox potential range of 1.3 V. We have found that the redox potential influenced the Faradaic efficiency of CO2 reduction to CO. However, no correlation between the redox potential and the Faradaic efficiency for methane was found. The lack of correlation could be attributed to the presence of a Cu-complex-derived catalyst deposited on the electrodes leading to a heterogeneous catalytic mechanism, which is controlled by the structure of the in situ deposited catalyst and not the redox potential of the pre-cursor Cu2+/1+ complexes.
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Affiliation(s)
- Kyuman Kim
- Intelligent Polymer Research Institute and ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Pawel Wagner
- Intelligent Polymer Research Institute and ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Klaudia Wagner
- Intelligent Polymer Research Institute and ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Attila J Mozer
- Intelligent Polymer Research Institute and ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW 2522, Australia
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Song S, Lee W, Lee Y, Cho KB, Lee J, Seo J. Two-Electron-Induced Reorganization of Cobalt Coordination and Metal-Ligand Cooperative Redox Shifting Co(I) Reactivity toward CO 2 Reduction. Inorg Chem 2023; 62:2326-2333. [PMID: 36691700 DOI: 10.1021/acs.inorgchem.2c04071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Electrochemical reorganization of complex structures is directly related to catalytic reactivity; thus, the geometric changes of catalysts induced by electron transfer should be considered to scrutinize the reaction mechanism. Herein, we studied electron-induced reorganization patterns of six-coordinate Co complexes with neutral N-donor ligands. Upon two-electron transfer into a Co center enclosed within a bulky π-acceptor ligand, the catalytic site exhibited different reorganization patterns depending on the ligand characteristics. While a bipyridyl ligand released Co-bound solvent (CH3CN) to open a reaction site, a phenanthroline ligand caused Co-Narm (side "arm" of NNN-ligand) bond dissociation. The first electron transfer occurred in the Co(II/I) reduction step and the second electron entered the bulky π-acceptor, of which redox steps were assigned from cyclic voltammograms, magnetic moment measurements, and DFT calculations. In comparison, the Co complex of [NNNNCH3-Co(CH3CN)3](PF6)2 ([1-(CH3CN)3](PF6)2) showed a high H2 evolution reactivity (HER), whereas a series of Co complexes with bulky π-acceptors such as [NNNNCH3-Co(L)(CH3CN)](PF6)2 (L = phen ([2-CH3CN](PF6)2), bpy ([3-CH3CN](PF6)2), [NNNNCH3-Co(tpy)](PF6)2 ([4](PF6)2), and [NNNCH2-Co(phen)(CH3CN)](PF6)2 ([5-CH3CN](PF6)2)) suppressed the HER but rather enhanced the CO2 reduction reaction. The metal-ligand cooperative redox steps enabled the shift of Co(I) reactivity toward CO2 reduction. Additionally, the amine pendant attached to the NNNNCH3-ligand could stabilize the CO2 reduction intermediate through the hydrogen-bonding interaction with the Co-CO2H adduct.
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Affiliation(s)
- Seungjin Song
- Department of Chemistry, Gwangju Institute of Science and Technology; Gwangju61005, Republic of Korea.,Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals(Inn-ECOSysChem), Gwangju Institute of Science and Technology; Gwangju61005, Republic of Korea
| | - Wonjung Lee
- Department of Chemistry, Gwangju Institute of Science and Technology; Gwangju61005, Republic of Korea.,Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals(Inn-ECOSysChem), Gwangju Institute of Science and Technology; Gwangju61005, Republic of Korea
| | - Youngseob Lee
- Department of Chemistry, Jeonbuk National University, Jeonju54896, Republic of Korea
| | - Kyung-Bin Cho
- Department of Chemistry, Jeonbuk National University, Jeonju54896, Republic of Korea
| | - Junseong Lee
- Department of Chemistry, Chonnam National University; Gwangju61186, Republic of Korea
| | - Junhyeok Seo
- Department of Chemistry, Gwangju Institute of Science and Technology; Gwangju61005, Republic of Korea.,Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals(Inn-ECOSysChem), Gwangju Institute of Science and Technology; Gwangju61005, Republic of Korea
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10
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Assaf EA, Gonell S, Chen CH, Miller AJM. Accessing and Photo-Accelerating Low-Overpotential Pathways for CO 2 Reduction: A Bis-Carbene Ruthenium Terpyridine Catalyst. ACS Catal 2022. [DOI: 10.1021/acscatal.2c03651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Eric A. Assaf
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599-3290, United States
| | - Sergio Gonell
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599-3290, United States
| | - Chun-Hsing Chen
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599-3290, United States
| | - Alexander J. M. Miller
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599-3290, United States
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11
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Kaeffer N, Leitner W. Electrocatalysis with Molecular Transition-Metal Complexes for Reductive Organic Synthesis. JACS AU 2022; 2:1266-1289. [PMID: 35783173 PMCID: PMC9241009 DOI: 10.1021/jacsau.2c00031] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
Electrocatalysis enables the formation or cleavage of chemical bonds by a genuine use of electrons or holes from an electrical energy input. As such, electrocatalysis offers resource-economical alternative pathways that bypass sacrificial, waste-generating reagents often required in classical thermal redox reactions. In this Perspective, we showcase the exploitation of molecular electrocatalysts for electrosynthesis, in particular for reductive conversion of organic substrates. Selected case studies illustrate that efficient molecular electrocatalysts not only are appropriate redox shuttles but also embrace the features of organometallic catalysis to facilitate and control chemical steps. From these examples, guidelines are proposed for the design of molecular electrocatalysts suited to the reduction of organic substrates. We finally expose opportunities brought by catalyzed electrosynthesis to functionalize organic backbones, namely using sustainable building blocks.
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