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Dilinaer AD, J Jobin G, Drover MW. A catalytic collaboration: pairing transition metals and Lewis acids for applications in organic synthesis. Dalton Trans 2024. [PMID: 38976284 DOI: 10.1039/d4dt01550a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
The use of metal catalysts to accelerate an organic transformation has proven indispensable for access to structural motifs having applications across medicinal, polymer, materials chemistry, and more. Most catalytic approaches have cast transition metals in the "leading role"; these players mediate important reactions such as C-C cross coupling and the hydrogenation of unsaturated bonds. These catalysts may require collaboration, featuring Lewis acidic or basic additives to promote a desired reaction outcome. Lewis acids can serve to accelerate reactions by way of substrate stabilization and/or activation, and as such, are valuable in optimizing catalytic transformations. A burgeoning area of chemical research which unifies these concepts has thus sought to develop transition metal complexes having ambiphilic (containing a Lewis basic and acidic unit) ligands. This approach takes advantage of metal-ligand cooperativity to increase the efficiency of a given chemical transformation, leveraging intramolecular interactions between a transition metal and an adjacent secondary ligand site. While this has shown significant potential to facilitate challenging and important transformations, there remains unexplored depth for creativity and future advancement. This Frontier highlights inter- and intramolecular combinations of transition metals and Lewis acids that together, provide a collaborative platform for chemical synthesis.
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Affiliation(s)
- A Dina Dilinaer
- Department of Chemistry, Western University, 1151 Richmond Street, London, ON, N8K 3G6, Canada.
| | - Gabriel J Jobin
- Department of Chemistry, Western University, 1151 Richmond Street, London, ON, N8K 3G6, Canada.
| | - Marcus W Drover
- Department of Chemistry, Western University, 1151 Richmond Street, London, ON, N8K 3G6, Canada.
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2
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Durfy CS, Zurakowski JA, Drover MW. A Blueprint for Secondary Coordination Sphere Editing: Approaches Toward Lewis-Acid Assisted Carbon Dioxide Co-Activation. CHEMSUSCHEM 2024; 17:e202400039. [PMID: 38358843 DOI: 10.1002/cssc.202400039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 02/17/2024]
Abstract
Carbon dioxide (CO2) is a potent greenhouse gas of environmental concern. Seeking to offer a solution to the "CO2-problem", the chemistry community has turned a focus toward transition metal complexes which can activate, reduce, and convert CO2 into carbon-based products. The design of such systems involves judicious selection of both metal and accompanying donor ligand; in part, these efforts are motivated by biological metalloenzymes that undertake similar transformations. As a design element, metal-ligand cooperativity, which leverages intramolecular interactions between a transition metal and an adjacent secondary ligand site, has been acknowledged as a vitally important component by the CO2 activation community. These systems offer a "push-pull" style of activation where electron density is chaperoned onto CO2 with an accompanying electrophile, such as a Lewis-acid, playing the role of acceptor. This pairing allows for the stabilization of reactive CxHyOz-containing intermediates and can bias CO2 product selectivity. In the laboratory, chemists can test hypotheses and ideas, enabling rationalization of why a given pairing of transition metal/Lewis-acid leads to selective CO2 reduction outcomes. This Concept identifies literature examples and highlights key design properties, allowing interested contributors to design, create, and implement novel systems for productive transformations of a small molecule (CO2) with huge potential impact.
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Affiliation(s)
- Connor S Durfy
- Department of Chemistry, Western University, 1151 Richmond Street, London, Ontario, Canada, N6A 3K7
| | - Joseph A Zurakowski
- Department of Chemistry, Western University, 1151 Richmond Street, London, Ontario, Canada, N6A 3K7
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, Canada, N9B 3P4
| | - Marcus W Drover
- Department of Chemistry, Western University, 1151 Richmond Street, London, Ontario, Canada, N6A 3K7
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3
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Beagan DM, Rivera C, Szymczak NK. Appended Lewis Acids Enable Dioxygen Reactivity and Catalytic Oxidations with Ni(II). J Am Chem Soc 2024; 146:12375-12385. [PMID: 38661576 PMCID: PMC11148854 DOI: 10.1021/jacs.3c12399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
We disclose a suite of Ni(II) complexes featuring secondary sphere Lewis acids of varied Lewis acidity and tether lengths. Several of these complexes feature atypical behavior of Ni(II): reactivity with O2 that occurs only in the presence of a tethered Lewis acid. In situ UV-vis spectroscopy revealed that, although adducts are stable at -40 °C, complexes containing 9-borabicyclo[3.3.1]nonane (9-BBN) Lewis acids underwent irreversible oxidative deborylation when warmed to room temperature. We computationally and experimentally identified that oxidative instability of appended 9-BBN moieties can be mitigated using weaker Lewis acids such as pinacolborane (BPin). These insights enabled the realization of catalytic reactions: hydrogen atom abstraction from phenols and room temperature oxygen atom transfer to PPh3.
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Affiliation(s)
- Daniel M Beagan
- University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Carolina Rivera
- University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Nathaniel K Szymczak
- University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
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Cruz TFC, Loupy V, Veiros LF. Zinc-Catalyzed Hydroboration of Carbon Dioxide Amplified by Borane-Tethered Heteroscorpionate Bis(Pyrazolyl)methane Ligands. Inorg Chem 2024; 63:8244-8256. [PMID: 38656156 PMCID: PMC11080050 DOI: 10.1021/acs.inorgchem.4c00500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 04/09/2024] [Accepted: 04/11/2024] [Indexed: 04/26/2024]
Abstract
The borane-functionalized (BR2) bis(3,5-dimethylpyrazolyl)methane (LH) ligands 1a (BR2: 9-borabicyclo[3.3.1]nonane or 9-BBN), 1b (BR2: BCy2), and 1c (BR2: B(C6F5)2) were synthesized by the allylation-hydroboration of LH. Metalation of 1a,b with ZnCl2 yielded the heteroscorpionate dichloride complexes [(1a,b)ZnCl2] 3a,b. The reaction of 1a with ZnEt2 led to the formation of the zwitterionic complex [Et(1a)ZnEt(THF)] 5. The reaction of complex 3a with two equivalents of KHBEt3 under a carbon dioxide (CO2) atmosphere gave rise to the formation of the dimeric bis(formate) complex [(1a)Zn(OCHO)2]2 8, in which its borane moieties intermolecularly stabilize the formate ligands of opposite metal centers. The allylated precursor Lallyl and its zinc dichloride, diethyl and bis(formate) complexes [(Lallyl)ZnCl2] 2, [(Lallyl)ZnEt2] 4, and [(Lallyl)Zn(OCHO)2] 7 were also isolated. The catalyst systems composed of 1 mol % of 3a or 3b and two equivalents of KHBEt3 hydroborated CO2 at 1 bar with pinacolborane (HBPin) to the methanol-level product H3COBPin (and PinBOBPin) in yields of 42 or 86%, respectively. The catalyst systems using the unfunctionalized complex [(LH)ZnCl2] 6 and KHBEt3 or KHBEt3/nOctBR2 (BR2: 9-BBN or BCy2) hydroborated CO2 to H3COBPin but in 2.5- to 6-fold lower activities than those exhibited by 3a,b/KHBEt3. The hydroboration of CO2 using 8 as a catalyst led to yields of 39-43%, comparable to those obtained with 3a/KHBEt3. The results confirmed that the catalytic intermediates benefit from the incorporated boranes' intra- or intermolecular stabilizations.
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Affiliation(s)
- Tiago F. C. Cruz
- Centro de Química
Estrutural, Institute of Molecular Sciences, Departamento de Engenharia
Química, Instituto Superior Técnico,
Universidade de Lisboa, Av. Rovisco Pais, 1049 001 Lisboa, Portugal
| | - Valentin Loupy
- Centro de Química
Estrutural, Institute of Molecular Sciences, Departamento de Engenharia
Química, Instituto Superior Técnico,
Universidade de Lisboa, Av. Rovisco Pais, 1049 001 Lisboa, Portugal
| | - Luís F. Veiros
- Centro de Química
Estrutural, Institute of Molecular Sciences, Departamento de Engenharia
Química, Instituto Superior Técnico,
Universidade de Lisboa, Av. Rovisco Pais, 1049 001 Lisboa, Portugal
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Jena S, Frenzen L, Chugh V, Wu J, Weyhermüller T, Auer AA, Werlé C. A Cooperative Cobalt-Driven System for One-Carbon Extension in the Synthesis of ( Z)-Silyl Enol Ethers from Aldehydes: Unlocking Regio- and Stereoselectivity. J Am Chem Soc 2023; 145:27922-27932. [PMID: 38086018 PMCID: PMC10755702 DOI: 10.1021/jacs.3c10491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/28/2023]
Abstract
The research presented herein explores a cobalt-based catalytic system, distinctively featuring a cooperative boron-centric element within its intricate ligand architecture. This system is strategically engineered to enable the integration of a singular carbon atom into aldehydes, a process culminating in the production of (Z)-silyl enol ethers. Beyond offering an efficient one-pot synthesis route, this method adeptly overcomes challenges inherent to conventional techniques, such as the need for large amounts of additives, restrictive functional group tolerance, and extreme reaction temperatures. Initial mechanistic studies suggest the potential role of a cobalt-carbene complex as a catalytically significant species and underscore the importance of the borane segment. Collectively, these observations highlight the potential of this system in advancing complex bond activation pursuits.
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Affiliation(s)
- Soumyashree Jena
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr
University Bochum, Universitätsstr.
150, 44801 Bochum, Germany
| | - Lars Frenzen
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Vishal Chugh
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr
University Bochum, Universitätsstr.
150, 44801 Bochum, Germany
| | - Jiajun Wu
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Thomas Weyhermüller
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Alexander A. Auer
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Christophe Werlé
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr
University Bochum, Universitätsstr.
150, 44801 Bochum, Germany
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Beagan DM, Kiernicki JJ, Zeller M, Szymczak NK. A Bidentate Ligand Featuring Ditopic Lewis Acids in the Second Sphere for Selective Substrate Capture and Activation. Angew Chem Int Ed Engl 2023; 62:e202218907. [PMID: 36720708 PMCID: PMC10023486 DOI: 10.1002/anie.202218907] [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: 12/21/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/02/2023]
Abstract
We present a ligand platform featuring appended ditopic Lewis acids to facilitate capture/activation of diatomic substrates. We show that incorporation of two 9-borabicyclo[3.3.1]nonane (9-BBN) units on a single carbon tethered to a pyridine pyrazole scaffold maintains a set of unquenched nitrogen donors available to coordinate FeII , ZnII , and NiII . Using hydride ion affinity and competition experiments, we establish an additive effect for ditopic secondary sphere boranes, compared to the monotopic analogue. These effects are exploited to achieve high selectivity for binding NO2 - in the presence of competitive anions such as F- and NO3 - . Finally, we demonstrate hydrazine capture within the second-sphere of metal complexes, followed by unique activation pathways to generate hydrazido and diazene ligands on Zn and Fe, respectively.
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Affiliation(s)
- Daniel M Beagan
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI 48109, USA
| | - John J Kiernicki
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI 48109, USA
- Present address: Drury University, Department of Chemistry and Physics, 900 North Benton Ave., Springfield, MO 65802, USA
| | - Matthias Zeller
- H.C. Brown Laboratory, Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN 47907, USA
| | - Nathaniel K Szymczak
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI 48109, USA
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7
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Su W, Rajeshkumar T, Xiang L, Maron L, Ye Q. Facile Synthesis of Uranium Complexes with a Pendant Borane Lewis Acid and 1,2-Insertion of CO into a U-N Bond. Angew Chem Int Ed Engl 2022; 61:e202212823. [PMID: 36256540 PMCID: PMC10099876 DOI: 10.1002/anie.202212823] [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: 08/30/2022] [Indexed: 11/18/2022]
Abstract
In this contribution, we illustrate uranium complexes bearing a pendant borate (i.e. 1 and 2) or a pendant borane (i.e. 3 and 4) moiety via reaction of the highly strained uranacycle I with various 3-coordinate boranes. Complexes 3 and 4 represent the first examples of uranium complexes with a pendant borane Lewis acid. Moreover, complex 3 was capable of activation of CO, delivering a new CO activation mode, and an abnormal CO 1,2-insertion pathway into a U-N bond. The importance of the pendant borane moiety was confirmed by the controlled experiments.
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Affiliation(s)
- Wei Su
- School of Chemistry and Environmental Engineering, Anhui Polytechnic University, 241000, Wuhu, China.,Department of Chemistry, Southern University of Science and Technology, 1088 Xueyuan Blvd., Xili, Nanshan District, 518055, Shenzhen, China
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nanoobjets, INSA, CNRS, UPS, Université de Toulouse, 31077, Toulouse, France
| | - Libo Xiang
- Department of Chemistry, Southern University of Science and Technology, 1088 Xueyuan Blvd., Xili, Nanshan District, 518055, Shenzhen, China.,Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nanoobjets, INSA, CNRS, UPS, Université de Toulouse, 31077, Toulouse, France
| | - Qing Ye
- Department of Chemistry, Southern University of Science and Technology, 1088 Xueyuan Blvd., Xili, Nanshan District, 518055, Shenzhen, China.,Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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