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Stroek W, Albrecht M. Application of first-row transition metal complexes bearing 1,2,3-triazolylidene ligands in catalysis and beyond. Chem Soc Rev 2024; 53:6322-6344. [PMID: 38726664 PMCID: PMC11181992 DOI: 10.1039/d4cs00021h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Indexed: 06/18/2024]
Abstract
Triazole-derived N-heterocyclic carbenes, triazolylidenes (trz) have become an interesting alternative to the ubiquitous Arduengo-type imidazole-derived carbenes, in part because they are stronger donors, and in other parts due to their versatile synthesis through different types of click reactions. While the use of trz ligands has initially focused on their coordination to precious metals for catalytic applications, the recent past has seen a growing interest in their impact on first-row transition metals. Coordination of trz ligands to such 3d metals is more challenging due to the orbital mismatch between the carbene and the 3d metal center, which also affects the stability of such complexes. Here we summarize the strategies that have been employed so far to overcome these challenges and to prepare first-row transition metal complexes containing at least one trz ligand. Both properties and reactivities of these trz complexes are comprehensively compiled, with a focus on photophysical properties and, in particular, on the application of these complexes in homogeneous catalysis. The diversity of catalytic transformations entailed with these trz 3d metal complexes as well as the record-high performance in some of the reactions underpins the benefits imparted by trz ligands.
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Affiliation(s)
- Wowa Stroek
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
| | - Martin Albrecht
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
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2
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Combining a Low Valent Molybdenum(0) Center with a Strongly σ-Donating Mesoionic Carbene Chelate Ligand—Synthesis and Structural Characterization. INORGANICS 2022. [DOI: 10.3390/inorganics10110216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Triazolylidene ligands belong to a class of N-heterocyclic carbenes of growing chemical interest. Their precursors are readily available using Click chemistry and, therefore, highly modular for tuning their electronic characteristics. Due to their notable donor properties, these ligands are particularly suitable for modulating the electronic properties of the central ions of their complexes. Here, a bidentate bistriazolylidene which is a particularly strong donor ligand is combined with a low valent molybdenum(0) center and four carbon monoxide molecules as co-ligands. The novel complex exhibits characteristic electrochemical and IR-spectroscopic behavior. An X-ray structural analysis provides metrical details which are not entirely in agreement with spectroscopic data, likely going back to crystal packing effects. In comparison with precursor and ligand SCXRD data, notable geometrical changes induced by the coordination of the ligand to the metal can be observed. The analyses strongly support the bistriazolylidene ligand as being a particularly good donor of electron density towards the central metal. Potentially, these findings may support, in the future, the design of potent catalysts for the reductive activation of small molecules.
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3
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Rudolf R, Neuman NI, Walter RRM, Ringenberg MR, Sarkar B. Mesoionic Imines (MIIs): Strong Donors and Versatile Ligands for Transition Metals and Main Group Substrates. Angew Chem Int Ed Engl 2022; 61:e202200653. [PMID: 35286004 PMCID: PMC9322014 DOI: 10.1002/anie.202200653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Indexed: 11/08/2022]
Abstract
We report the synthesis and the reactivity of 1,2,3‐triazolin‐5‐imine type mesoionic imines (MIIs). The MIIs are accessible by a base‐mediated cycloaddition between a substituted acetonitrile and an aromatic azide, methylation by established routes and subsequent deprotonation. C=O‐stretching frequencies in MII−CO2 and −Rh(CO)2Cl complexes were used to determine the overall donor strength. The MIIs are stronger donors than the N‐heterocyclic imines (NHIs). MIIs are excellent ligands for main group elements and transition metals in which they display substituent‐induced fluorine‐specific interactions and undergo C−H activation. DFT calculations gave insights into the frontier orbitals of the MIIs. The calculations predict a relatively small HOMO–LUMO gap compared to other related ligands. MIIs are potentially able to act as both π‐donor and π‐acceptor ligands. This report highlights the potential of MIIs to display exciting properties with a huge potential for future development.
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Affiliation(s)
- Richard Rudolf
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Nicolás I. Neuman
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
- Instituto de Desarrollo Tecnológico para la Industria Química INTEC, UNL-CONICET Predio CONICET Santa Fe “Dr. Alberto Cassano” Colectora Ruta Nacional 168, Km 0 Paraje El Pozo S3000ZAA) Santa Fe Argentina
| | - Robert R. M. Walter
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Mark. R. Ringenberg
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Biprajit Sarkar
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
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4
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Huang S, Wu Y, Huang L, Hu C, Yan X. Synthesis, Characterization and Photophysical Properties of Mesoionic N-Heterocyclic Imines. Chem Asian J 2022; 17:e202200281. [PMID: 35502454 DOI: 10.1002/asia.202200281] [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: 03/19/2022] [Revised: 04/19/2022] [Indexed: 11/09/2022]
Abstract
N -heterocyclic imines are widely used in transition-metal chemistry, main-group chemistry as well as catalysis, due to their enhanced basicity and nucleophilicity which benefit from their ylidic form. As their analogs, mesoionic N -heterocyclic imines, which feature more highly ylidic form, is still in its infancy though excellent works also achieved. Here we reported the synthesis, characterization and photophysical properties of mesoionic N -heterocyclic imines. TD-DFT are employed to get deeper insight into the mechanism of the photophysical behaviors. The unsubstituted mesoionic N-heterocyclic imines ( 1-3 ) displayed considerable quantum yields (QY: up to 43.8%) and could be potentially applied as luminescent materials.
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Affiliation(s)
| | - Yixin Wu
- Renmin University of China, Chemistry, CHINA
| | | | - Chubin Hu
- Renmin University of China, Chemistry, CHINA
| | - Xiaoyu Yan
- Renmin University of China, Department of Chemistry, Renmin University of China, Beijing 100872, China, 100872, Beijing, CHINA
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5
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Rudolf R, Neuman NI, Walter RRM, Ringenberg MR, Sarkar B. Mesoionische Imine (MIIs): Starke Donoren und vielseitige Liganden für Übergangsmetalle und Hauptgruppensubstrate. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Richard Rudolf
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Nicolás I. Neuman
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
- Instituto de Desarrollo Tecnológico para la Industria Química CINTEC, VUNL-CONICET VPredio CONICET Santa Fe “Dr. Alberto Cassano“ Colectora Ruta Nacional 168, Km 0 Paraje El Pozo S3000ZAA) Santa Fe Argentinien
| | - Robert R. M. Walter
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Mark. R. Ringenberg
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Biprajit Sarkar
- Lehrstuhl für Anorganische Koordinationschemie Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
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6
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Maity R, Sarkar B. Chemistry of Compounds Based on 1,2,3-Triazolylidene-Type Mesoionic Carbenes. JACS AU 2022; 2:22-57. [PMID: 35098220 PMCID: PMC8790748 DOI: 10.1021/jacsau.1c00338] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Indexed: 05/04/2023]
Abstract
Mesoionic carbenes (MICs) of the 1,2,3-triazolylidene type have established themselves as a popular class of compounds over the past decade. Primary reasons for this popularity are their modular synthesis and their strong donor properties. While such MICs have mostly been used in combination with transition metals, the past few years have also seen their utility together with main group elements. In this paper, we present an overview of the recent developments on this class of compounds that include, among others, (i) cationic and anionic MIC ligands, (ii) the donor/acceptor properties of these ligands with a focus on the several methods that are known for estimating such donor/acceptor properties, (iii) a detailed overview of 3d metal complexes and main group compounds with these MIC ligands, (iv) results on the redox and photophysical properties of compounds based on MIC ligands, and (v) an overview on electrocatalysis, redox-switchable catalysis, and small-molecule activation to highlight the applications of compounds based on MIC ligands in contemporary chemistry. By discussing several aspects from the synthetic, spectroscopic, and application point of view of these classes of compounds, we highlight the state of the art of compounds containing MICs and present a perspective for future research in this field.
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Affiliation(s)
- Ramananda Maity
- Dr.
R. Maity Department of Chemistry, University
of Calcutta, 92, A. P.
C. Road, Kolkata 700009, India
| | - Biprajit Sarkar
- Prof.
Dr. B. Sarkar Lehrstuhl für Anorganische Koordinationschemie,
Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
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7
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Nößler M, Hunger D, Neuman NI, Reimann M, Reichert F, Winkler M, Klein J, Bens T, Suntrup L, Demeshko S, Stubbe J, Kaupp M, van Slageren J, Sarkar B. Fluorinated Click-Derived Tripodal Ligands Drive Spin Crossover in both Iron(II) and Cobalt(II) Complexes. Dalton Trans 2022; 51:10507-10517. [DOI: 10.1039/d2dt01005d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Control of the spin state of metal complexes is important because it leads to a precise control over the physical properties and the chemical reactivity of the metal complexes. Currently,...
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8
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Neururer F, Liu S, Leitner D, Baltrun M, Fisher KR, Kopacka H, Wurst K, Daumann LJ, Munz D, Hohloch S. Mesoionic Carbenes in Low- to High-Valent Vanadium Chemistry. Inorg Chem 2021; 60:15421-15434. [PMID: 34590834 PMCID: PMC8527456 DOI: 10.1021/acs.inorgchem.1c02087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Indexed: 12/12/2022]
Abstract
We report the synthesis of vanadium(V) oxo complex 1 with a pincer-type dianionic mesoionic carbene (MIC) ligand L1 and the general formula [VOCl(L1)]. A comparison of the structural (SC-XRD), electronic (UV-vis), and electrochemical (cyclic voltammetry) properties of 1 with the benzimidazolinylidene congener 2 (general formula [VOCl(L2)]) shows that the MIC is a stronger donor also for early transition metals with low d-electron population. Since electrochemical studies revealed both complexes to be reversibly reduced, the stronger donor character of MICs was not only demonstrated for the vanadium(V) but also for the vanadium(IV) oxidation state by isolating the reduced vanadium(IV) complexes [Co(Cp*)2][1] and [Co(Cp*)2][2] ([Co(Cp*)2] = decamethylcobaltocenium). The electronic structures of the compounds were investigated by computational methods. Complex 1 was found to be a moderate precursor for salt metathesis reactions, showing selective reactivity toward phenolates or secondary amides, but not toward primary amides and phosphides, thiophenols, or aryls/alkyls donors. Deoxygenation with electron-rich phosphines failed to give the desired vanadium(III) complex. However, treatment of the deprotonated ligand precursor with vanadium(III) trichloride resulted in the clean formation of the corresponding MIC vanadium(III) complex 6, which undergoes a clean two-electron oxidation with organic azides yielding the corresponding imido complexes. The reaction with TMS-N3 did not afford a nitrido complex, but instead the imido complex 10. This study reveals that, contrary to popular belief, MICs are capable of supporting early transition-metal complexes in a variety of oxidation states, thus making them promising candidates for the activation of small molecules and redox catalysis.
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Affiliation(s)
- Florian
R. Neururer
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Shenyu Liu
- Faculty
of Science, Department of Chemistry, University
of Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Daniel Leitner
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Marc Baltrun
- Faculty
of Science, Department of Chemistry, University
of Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Katherine R. Fisher
- Department
Chemie, Ludwigs-Maximilians-University Munich, Butenandtstraße 5-13 Haus D, 81377 Munich, Germany
| | - Holger Kopacka
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Klaus Wurst
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Lena J. Daumann
- Department
Chemie, Ludwigs-Maximilians-University Munich, Butenandtstraße 5-13 Haus D, 81377 Munich, Germany
| | - Dominik Munz
- Fakultät
NT, Inorganic Chemistry: Coordination Chemistry, Saarland University, Campus C4.1, 66123 Saarbrücken, Germany
| | - Stephan Hohloch
- Institute
of Inorganic, General and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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9
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Mono‐ and Di‐Mesoionic Carbene‐Boranes: Synthesis, Structures and Utility as Reducing Agents. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100273] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Stubbe J, Neuman NI, McLellan R, Sommer MG, Nößler M, Beerhues J, Mulvey RE, Sarkar B. Isomerization Reactions in Anionic Mesoionic Carbene-Borates and Control of Properties and Reactivities in the Resulting Co II Complexes through Agostic Interactions. Angew Chem Int Ed Engl 2021; 60:499-506. [PMID: 33080102 PMCID: PMC7839553 DOI: 10.1002/anie.202013376] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Indexed: 12/31/2022]
Abstract
We present herein anionic borate-based bi-mesoionic carbene compounds of the 1,2,3-triazol-4-ylidene type that undergo C-N isomerization reactions. The isomerized compounds are excellent ligands for CoII centers. Strong agostic interactions with the "C-H"-groups of the cyclohexyl substituents result in an unusual low-spin square planar CoII complex, which is unreactive towards external substrates. Such agostic interactions are absent in the complex with phenyl substituents on the borate backbone. This complex displays a high-spin tetrahedral CoII center, which is reactive towards external substrates including dioxygen. To the best of our knowledge, this is also the first investigation of agostic interactions through single-crystal EPR spectroscopy. We conclusively show here that the structure and properties of these CoII complexes can be strongly influenced through interactions in the secondary coordination sphere. Additionally, we unravel a unique ligand rearrangement for these classes of anionic mesoionic carbene-based ligands.
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Affiliation(s)
- Jessica Stubbe
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
| | - Nicolás I. Neuman
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
- Instituto de Desarrollo Tecnológico para la Industria Química CCT Santa Fe CONICET-UNLColectora Ruta Nacional 168, Km 472, Paraje El Pozo3000Santa FeArgentina
| | - Ross McLellan
- WestCHEMDepartment of Pure & Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Michael G. Sommer
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
| | - Maite Nößler
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
| | - Julia Beerhues
- Lehrstuhl für Anorganische KoordinationschemieInstitut für Anorganische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Robert E. Mulvey
- WestCHEMDepartment of Pure & Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Biprajit Sarkar
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
- Lehrstuhl für Anorganische KoordinationschemieInstitut für Anorganische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
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