1
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Gorgas N, Stadler B, White AJP, Crimmin MR. Vinylic C-H Activation of Styrenes by an Iron-Aluminum Complex. J Am Chem Soc 2024; 146:4252-4259. [PMID: 38303600 PMCID: PMC10870711 DOI: 10.1021/jacs.3c14281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 02/03/2024]
Abstract
The oxidative addition of sp2 C-H bonds of alkenes to single-site transition-metal complexes is complicated by the competing π-coordination of the C═C double bond, limiting the examples of this type of reactivity and onward applications. Here, we report the C-H activation of styrenes by a well-defined bimetallic Fe-Al complex. These reactions are highly selective, resulting in the (E)-β-metalation of the alkene. For this bimetallic system, alkene binding appears to be essential for the reaction to occur. Experimental and computational insights suggest an unusual reaction pathway in which a (2 + 2) cycloaddition intermediate is directly converted into the hydrido vinyl product via an intramolecular sp2 C-H bond activation across the two metals. The key C-H cleavage step proceeds through a highly asynchronous transition state near the boundary between a concerted and a stepwise mechanism influenced by the resonance stabilization ability of the aryl substituent. The metalated alkenes can be further functionalized, which has been demonstrated by the (E)-selective phosphination of the employed styrenes.
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Affiliation(s)
- Nikolaus Gorgas
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London W12 0BZ, U.K.
- Institute
of Applied Synthetic Chemistry, Vienna University
of Technology, Getreidemarkt
9, 1060 Vienna, Austria
| | - Benedek Stadler
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London W12 0BZ, U.K.
| | - Andrew J. P. White
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London W12 0BZ, U.K.
| | - Mark R. Crimmin
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London W12 0BZ, U.K.
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2
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Lachguar A, Pichugov AV, Neumann T, Dubrawski Z, Camp C. Cooperative activation of carbon-hydrogen bonds by heterobimetallic systems. Dalton Trans 2024; 53:1393-1409. [PMID: 38126396 PMCID: PMC10804807 DOI: 10.1039/d3dt03571a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023]
Abstract
The direct activation of C-H bonds has been a rich and active field of organometallic chemistry for many years. Recently, incredible progress has been made and important mechanistic insights have accelerated research. In particular, the use of heterobimetallic complexes to heterolytically activate C-H bonds across the two metal centers has seen a recent surge in interest. This perspective article aims to orient the reader in this fast moving field, highlight recent progress, give design considerations for further research and provide an optimistic outlook on the future of catalytic C-H functionalization with heterobimetallic complexes.
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Affiliation(s)
- Abdelhak Lachguar
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
| | - Andrey V Pichugov
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
| | - Till Neumann
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
| | - Zachary Dubrawski
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
| | - Clément Camp
- Université de Lyon, Institut de Chimie de Lyon, Laboratory of Catalysis, Polymerization, Processes & Materials, CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
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3
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Lynch JR, Kennedy AR, Barker J, Mulvey RE. Modification of a Common β-diketiminate NacNac Framework via Sequential Lithiation and Small Molecule Insertion. Chemistry 2023:e202303373. [PMID: 38032346 DOI: 10.1002/chem.202303373] [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: 10/13/2023] [Revised: 11/23/2023] [Accepted: 11/30/2023] [Indexed: 12/01/2023]
Abstract
A widely utilised class of ligands in synthesis and catalysis, β-diketiminate (BDI) or NacNac compounds were initially considered innocent in the sense that they remained intact in all their applications. That changed when the γ-C-H unit of their NCCCN backbone was found to engage in reactions with electrophiles. Here, we show that this special reactivity can be used advantageously to prepare tripodal modifications of the common NacNac ligand derived from 2,6-diisopropylphenyl-β-methyldiketimine [NacNacH (Me, Dipp)]. Lithiation to give NacNacLi, followed by reactions with isocyanates, isothiocyanates and a carbodiimide, have afforded a series of tripodal NacNac variants having N,N,N,O; N,N,N,S; or N,N,N,N potential dentation sites, many of which have been crystallographically characterised. Distinct ligating modes of these new ligands have been elucidated through the crystal structures of their lithiated derivatives.
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Affiliation(s)
- Jennifer R Lynch
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Alan R Kennedy
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Jim Barker
- Innospec Ltd., Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, UK
| | - Robert E Mulvey
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
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Fernández S, Fernando S, Planas O. Cooperation towards nobility: equipping first-row transition metals with an aluminium sword. Dalton Trans 2023; 52:14259-14286. [PMID: 37740303 DOI: 10.1039/d3dt02722h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
The exploration for noble metals substitutes in catalysis has become a highly active area of research, driven by the pursuit of sustainable chemical processes. Although the utilization of base metals holds great potential as an alternative, their successful implementation in predictable catalytic processes necessitates the development of appropriate ligands. Such ligands must be capable of controlling their intricate redox chemistry and promote two-electron events, thus mimicking well-established organometallic processes in noble metal catalysis. While numerous approaches for infusing nobility to base metals have been explored, metal-ligand cooperation has garnered significant attention in recent years. Within this context, aluminium-based ligands offer interesting features to fine-tune the activity of metal centres, but their application in base metal catalysis remains largely unexplored. This perspective seeks to highlight the most recent breakthroughs in the reactivity of heterobimetallic aluminium-base-metal complexes, while also showcasing their potential to develop novel and predictable catalytic transformations. By turning the spotlight on such heterobimetallic species, we aim to inspire chemists to explore aluminium-base-metal species and expand the range of their applications as catalysts.
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Affiliation(s)
- Sergio Fernández
- Queen Mary University of London, School of Physical and Chemical Sciences, Department of Chemistry, Mile End Road, London E1 4NS, UK.
| | - Selwin Fernando
- Queen Mary University of London, School of Physical and Chemical Sciences, Department of Chemistry, Mile End Road, London E1 4NS, UK.
| | - Oriol Planas
- Queen Mary University of London, School of Physical and Chemical Sciences, Department of Chemistry, Mile End Road, London E1 4NS, UK.
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Stadler B, Gorgas N, White AJP, Crimmin MR. Double Deprotonation of CH 3 CN by an Iron-Aluminium Complex. Angew Chem Int Ed Engl 2023; 62:e202219212. [PMID: 36799769 PMCID: PMC10946928 DOI: 10.1002/anie.202219212] [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: 12/28/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 02/18/2023]
Abstract
Herein we present the first double deprotonation of acetonitrile (CH3 CN) using two equivalents of a bimetallic iron-aluminium complex. The products of this reaction contain an exceeding simple yet rare [CHCN]2- dianion moiety that bridges two metal fragments. DFT calculations suggest that the bonding to the metal centres occurs through heavily polarised covalent interactions. Mechanistic studies reveal the intermediacy of a monomeric [CH2 CN]- complex, which has been characterised in situ. Our findings provide an important example in which a bimetallic metal complex achieves a new type of reactivity not previously encountered with monometallic counterparts.[1, 2] The isolation of a [CHCN]2- dianion through simple deprotonation of CH3 CN also offers the possibility of establishing a broader chemistry of this motif.
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Affiliation(s)
- Benedek Stadler
- Department of ChemistryImperial College London White CityLondonW12 0BZUK
| | - Nikolaus Gorgas
- Department of ChemistryImperial College London White CityLondonW12 0BZUK
- Institute of Applied Synthetic ChemistryVienna University of TechnologyGetreidemarkt 91060ViennaAustria
| | - Andrew J. P. White
- Department of ChemistryImperial College London White CityLondonW12 0BZUK
| | - Mark R. Crimmin
- Department of ChemistryImperial College London White CityLondonW12 0BZUK
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Stadler B, Gorgas N, White AJP, Crimmin MR. Double Deprotonation of CH 3CN by an Iron-Aluminium Complex. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202219212. [PMID: 38516673 PMCID: PMC10952947 DOI: 10.1002/ange.202219212] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Indexed: 03/23/2024]
Abstract
Herein we present the first double deprotonation of acetonitrile (CH3CN) using two equivalents of a bimetallic iron-aluminium complex. The products of this reaction contain an exceeding simple yet rare [CHCN]2- dianion moiety that bridges two metal fragments. DFT calculations suggest that the bonding to the metal centres occurs through heavily polarised covalent interactions. Mechanistic studies reveal the intermediacy of a monomeric [CH2CN]- complex, which has been characterised in situ. Our findings provide an important example in which a bimetallic metal complex achieves a new type of reactivity not previously encountered with monometallic counterparts.[1, 2] The isolation of a [CHCN]2- dianion through simple deprotonation of CH3CN also offers the possibility of establishing a broader chemistry of this motif.
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Affiliation(s)
- Benedek Stadler
- Department of ChemistryImperial College London White CityLondonW12 0BZUK
| | - Nikolaus Gorgas
- Department of ChemistryImperial College London White CityLondonW12 0BZUK
- Institute of Applied Synthetic ChemistryVienna University of TechnologyGetreidemarkt 91060ViennaAustria
| | - Andrew J. P. White
- Department of ChemistryImperial College London White CityLondonW12 0BZUK
| | - Mark R. Crimmin
- Department of ChemistryImperial College London White CityLondonW12 0BZUK
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