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Samayoa-Oviedo HY, Knorke H, Warneke J, Laskin J. Spontaneous ligand loss by soft landed [Ni(bpy) 3] 2+ ions on perfluorinated self-assembled monolayer surfaces. Chem Sci 2024; 15:10770-10783. [PMID: 39027285 PMCID: PMC11253159 DOI: 10.1039/d4sc02527j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/11/2024] [Indexed: 07/20/2024] Open
Abstract
Transition metal (TM) complexes are widely used in catalysis, photochemical energy conversion, and sensing. Understanding factors that affect ligand loss from TM complexes at interfaces is important both for generating catalytically-active undercoordinated TM complexes and for controlling the degradation pathways of photosensitizers and photoredox catalysts. Herein, we demonstrate that well-defined TM complexes prepared on surfaces using ion soft landing undergo substantial structural rearrangements resulting in ligand loss and formation of both stable and reactive undercoordinated species. We employ nickel bipyridine (Ni-bpy) cations as a model system and explore their structural reorganization on surfaces using a combination of experimental and computational approaches. The controlled preparation of surface layers by mass-selected deposition of [Ni(bpy)3]2+ cations provides insights into the chemical reactivity of these species on surfaces. Both surface characterization using mass spectrometry and electronic structure calculations using density functional theory (DFT) indicate that [Ni(bpy)3]2+ undergoes a substantial geometry distortion on surfaces in comparison with its gas-phase structure. This distortion reduces the ligand binding energy and facilitates the formation of the undercoordinated [Ni(bpy)2]2+. Additionally, charge reduction by the soft landed [Ni(bpy)3]2+ facilitates ligand loss. We observe that ligand loss is inhibited by co-depositing [Ni(bpy)3]2+ with a stable anion such as closo-dodecaborate dianion, [B12F12]2-. The strong electrostatic interaction between [Ni(bpy)3]2+ and [B12F12]2- diminishes the distortion of the cation due to interactions with the surface. This interaction stabilizes the soft landed cation by reducing the extent of charge reduction and its structural reorganization. Overall, this study shows the intricate interplay of charge state, ion surface interactions, and stabilization by counterions on the structure and reactivity of metal complexes on surfaces. The combined experimental and computational approach used in this study offers detailed insights into factors that affect the integrity and stability of active species relevant to energy production and catalysis.
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Affiliation(s)
- Hugo Y Samayoa-Oviedo
- Department of Chemistry, Purdue University West Lafayette IN 47907 USA +1-765-494-5434
| | - Harald Knorke
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig 04103 Leipzig Germany
| | - Jonas Warneke
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig 04103 Leipzig Germany
- Leibniz Institut für Oberflächenmodifizierung (IOM) Permoserstraße 15 04318 Leipzig Germany
| | - Julia Laskin
- Department of Chemistry, Purdue University West Lafayette IN 47907 USA +1-765-494-5434
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Li L, Wang X, Fu N. Electrochemical Nickel-Catalyzed Hydrogenation. Angew Chem Int Ed Engl 2024; 63:e202403475. [PMID: 38504466 DOI: 10.1002/anie.202403475] [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: 02/19/2024] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 03/21/2024]
Abstract
Olefin hydrogenation is one of the most important transformations in organic synthesis. Electrochemical transition metal-catalyzed hydrogenation is an attractive approach to replace the dangerous hydrogen gas with electrons and protons. However, this reaction poses major challenges due to rapid hydrogen evolution reaction (HER) of metal-hydride species that outcompetes alkene hydrogenation step, and facile deposition of the metal catalyst at the electrode that stalls reaction. Here we report an economical and efficient strategy to achieve high selectivity for hydrogenation reactivity over the well-established HER. Using an inexpensive and bench-stable nickel salt as the catalyst, this mild reaction features outstanding substrate generality and functional group compatibility, and distinct chemoselectivity. In addition, hydrodebromination of alkyl and aryl bromides could be realized using the same reaction system with a different ligand, and high chemoselectivity between hydrogenation and hydrodebromination could be achieved through ligand selection. The practicability of our method has been demonstrated by the success of large-scale synthesis using catalytic amount of electrolyte and a minimal amount of solvent. Cyclic voltammetry and kinetic studies were performed, which support a NiII/0 catalytic cycle and the pre-coordination of the substrate to the nickel center.
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Affiliation(s)
- Liubo Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xinyi Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Niankai Fu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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3
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Guo P, Xu Y, Wu H, Zhang L. Membrane-Free Selective Semi-Hydrogenation of Alkynes Over an In Situ Formed Copper Nanoparticle Electrode. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2401107. [PMID: 38530045 DOI: 10.1002/smll.202401107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/12/2024] [Indexed: 03/27/2024]
Abstract
Selective semi-hydrogenation of alkynes is a significant reaction for preparing functionalized alkenes. Electrochemical semi-hydrogenation presents a sustainable alternative to the traditional thermal process. In this research, affordable copper acetylacetonate is employed as a catalyst precursor for the electrocatalytic hydrogenation of alkynes, using MeOH as the hydrogen source in an undivided cell. Good to excellent yields for both aromatic and aliphatic internal/terminal alkynes are obtained under constant current conditions. Notably, up to 99% Z selectivity is achieved for various internal alkynes. Mechanistic investigations revealed the formation of copper nanoparticles (NPs) at the cathode during electrolysis, acting as the catalyst for the selective semireduction of alkynes. The copper NPs deposited cathode demonstrated reusable for further hydrogenation.
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Affiliation(s)
- Pengyu Guo
- School of Chemistry and Material Sciences, Hangzhou Institute of Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
| | - Yousen Xu
- School of Chemistry and Material Sciences, Hangzhou Institute of Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
| | - Hao Wu
- School of Chemistry and Material Sciences, Hangzhou Institute of Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
| | - Lei Zhang
- School of Chemistry and Material Sciences, Hangzhou Institute of Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
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4
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Czaikowski ME, Anferov SW, Tascher AP, Anderson JS. Electrocatalytic Semihydrogenation of Terminal Alkynes Using Ligand-Based Transfer of Protons and Electrons. J Am Chem Soc 2024; 146:476-486. [PMID: 38163759 DOI: 10.1021/jacs.3c09885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Alkyne semihydrogenation is a broadly important transformation in chemical synthesis. Here, we introduce an electrochemical method for the selective semihydrogenation of terminal alkynes using a dihydrazonopyrrole Ni complex capable of storing an H2 equivalent (2H+ + 2e-) on the ligand backbone. This method is chemoselective for the semihydrogenation of terminal alkynes over internal alkynes or alkenes. Mechanistic studies reveal that the transformation is concerted and Z-selective. Calculations support a ligand-based hydrogen-atom transfer pathway instead of a hydride mechanism, which is commonly invoked for transition metal hydrogenation catalysts. The synthesis of the proposed intermediates demonstrates that the catalytic mechanism proceeds through a reduced formal Ni(I) species. The high yields for terminal alkene products without over-reduction or oligomerization are among the best reported for any homogeneous catalyst. Furthermore, the metal-ligand cooperative hydrogen transfer enabled with this system directs the efficient flow of H atom equivalents toward alkyne reduction rather than hydrogen evolution, providing a blueprint for applying similar strategies toward a wide range of electroreductive transformations.
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Affiliation(s)
- Maia E Czaikowski
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Sophie W Anferov
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Alex P Tascher
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - John S Anderson
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
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Byun S, Hwang MU, Wise HR, Bay AV, Cheong PHY, Scheidt KA. Light-Driven Enantioselective Carbene-Catalyzed Radical-Radical Coupling. Angew Chem Int Ed Engl 2023; 62:e202312829. [PMID: 37845183 PMCID: PMC10841513 DOI: 10.1002/anie.202312829] [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: 08/31/2023] [Revised: 10/13/2023] [Accepted: 10/13/2023] [Indexed: 10/18/2023]
Abstract
An enantioselective carbene-catalyzed radical-radical coupling of acyl imidazoles and racemic Hantzsch esters is disclosed. This method involves the coupling of an N-heterocyclic carbene-derived ketyl radical and a secondary sp3 -carbon radical and allows access to chiral α-aryl aliphatic ketones in moderate-to-good yields and enantioselectivities without any competitive epimerization. The utility of this protocol is highlighted by the late-stage functionalization of various pharmaceutical compounds and is further demonstrated by the transformation of the enantioenriched products to biologically relevant molecules. Computational investigations reveal the N-heterocyclic carbene controls the double-facial selectivity of the ketyl radical and the alkyl radicals, respectively.
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Affiliation(s)
- Seunghwan Byun
- Department of Chemistry, Northwestern University Silverman Hall, Evanston, Illinois 60208 (USA)
| | - Meemie U. Hwang
- Department of Chemistry, Northwestern University Silverman Hall, Evanston, Illinois 60208 (USA)
| | - Henry R. Wise
- Department of Chemistry, Oregon State University 153 Gilbert Hall, Corvallis, Oregon 97331 (USA)
| | - Anna V. Bay
- Department of Chemistry, Northwestern University Silverman Hall, Evanston, Illinois 60208 (USA)
| | - Paul H.-Y. Cheong
- Department of Chemistry, Oregon State University 153 Gilbert Hall, Corvallis, Oregon 97331 (USA)
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Kleinhaus JT, Wolf J, Pellumbi K, Wickert L, Viswanathan SC, Junge Puring K, Siegmund D, Apfel UP. Developing electrochemical hydrogenation towards industrial application. Chem Soc Rev 2023; 52:7305-7332. [PMID: 37814786 DOI: 10.1039/d3cs00419h] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Electrochemical hydrogenation reactions gained significant attention as a sustainable and efficient alternative to conventional thermocatalytic hydrogenations. This tutorial review provides a comprehensive overview of the basic principles, the practical application, and recent advances of electrochemical hydrogenation reactions, with a particular emphasis on the translation of these reactions from lab-scale to industrial applications. Giving an overview on the vast amount of conceivable organic substrates and tested catalysts, we highlight the challenges associated with upscaling electrochemical hydrogenations, such as mass transfer limitations and reactor design. Strategies and techniques for addressing these challenges are discussed, including the development of novel catalysts and the implementation of scalable and innovative cell concepts. We furthermore present an outlook on current challenges, future prospects, and research directions for achieving widespread industrial implementation of electrochemical hydrogenation reactions. This work aims to provide beginners as well as experienced electrochemists with a starting point into the potential future transformation of electrochemical hydrogenations from a laboratory curiosity to a viable technology for sustainable chemical synthesis on an industrial scale.
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Affiliation(s)
- Julian T Kleinhaus
- Inorganic Chemistry I, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
| | - Jonas Wolf
- Inorganic Chemistry I, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, Germany
| | - Kevinjeorjios Pellumbi
- Inorganic Chemistry I, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, Germany
| | - Leon Wickert
- Inorganic Chemistry I, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, Germany
| | - Sangita C Viswanathan
- Inorganic Chemistry I, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, Germany
| | - Kai Junge Puring
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, Germany
| | - Daniel Siegmund
- Inorganic Chemistry I, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, Germany
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