1
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Franc M, Schulz J, Štěpnička P. Facile synthesis and bonding of 4-ferrocenyl-1,2,4-triazol-5-ylidene complexes. Dalton Trans 2024; 53:11445-11453. [PMID: 38904982 DOI: 10.1039/d4dt01433b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Ferrocene-substituted carbenes have emerged as attractive, redox-active ligands. However, among the compounds studied to date, ferrocenylated 1,2,4-triazol-5-ylidenes, which are closely related to the archetypal imidazol-2-ylidenes, are still unknown. Here, we demonstrate that the triazolium salt [CHN(Me)NCHN(Fc)]I (2; Fc = ferrocenyl), obtained by alkylation of 4-ferrocenyl-4H-1,2,4-triazole (1) with MeI, reacts selectively with metal alkoxide/hydroxide precursors [(cod)Rh(OMe)]2 and [(IPr)Au(OH)] (cod = cycloocta-1,5-diene, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) to produce the ferrocene-substituted 1,2,4-triazol-5-ylidene complexes [(cod)RhI{CN(Me)NCHN(Fc)}] and [(IPr)Au{CN(Me)NCHN(Fc)}]I in good yields. The complexes were characterised by NMR and IR spectroscopy, mass spectrometry, cyclic voltammetry, and single-crystal X-ray diffraction analysis. Density function theory (DFT) calculations were used to rationalise the electrochemical behaviour of the carbene complexes and to elucidate the bonding situation in these compounds. An analysis using intrinsic bond orbitals (IBOs) revealed that the 1,2,4-triazol-5-ylidene ligand exerted a strong trans influence and showed a synergistic stabilisation by the negative inductive and positive π-donor effects of the nitrogen atoms adjacent to the carbene carbon atom; these effects were enhanced by conjugation with the CHN bond at the exterior, similar to that in imidazol-2-ylidenes.
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Affiliation(s)
- Michal Franc
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Jiří Schulz
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Petr Štěpnička
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
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2
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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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3
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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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4
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Affiliation(s)
- Han Vinh Huynh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore, Republic of Singapore
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5
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Galiana‐Cameo M, Passarelli V, Pérez‐Torrente JJ, Di Giuseppe A, Castarlenas R. Variation on the π‐Acceptor Ligand within a Rh
I
−N‐Heterocyclic Carbene Framework: Divergent Catalytic Outcomes for Phenylacetylene‐Methanol Transformations. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100399] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- María Galiana‐Cameo
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) Universidad de Zaragoza-CSIC C/Pedro Cerbuna 12 CP 50009 Zaragoza Spain
| | - Vincenzo Passarelli
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) Universidad de Zaragoza-CSIC C/Pedro Cerbuna 12 CP 50009 Zaragoza Spain
| | - Jesús J. Pérez‐Torrente
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) Universidad de Zaragoza-CSIC C/Pedro Cerbuna 12 CP 50009 Zaragoza Spain
| | - Andrea Di Giuseppe
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) Universidad de Zaragoza-CSIC C/Pedro Cerbuna 12 CP 50009 Zaragoza Spain
- Dipartimento di Scienze Fisiche e Chimiche Università dell'Aquila Via Vetoio 67100 Coppito (AQ) Italy
| | - Ricardo Castarlenas
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) Universidad de Zaragoza-CSIC C/Pedro Cerbuna 12 CP 50009 Zaragoza Spain
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6
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Triazole-tethered ferrocene-quinoline conjugates: solid-state structure analysis, electrochemistry and theoretical calculations. Struct Chem 2021. [DOI: 10.1007/s11224-021-01801-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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7
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Sawaguchi D, Hayakawa S, Sakuma M, Niitsuma K, Kase D, Michii S, Ozawa M, Sakai Y, Sakamaki K, Ueyama K, Haraguchi R. Improved Synthesis of 1,2,3‐Triazolium Salts via Oxidative [3+2] Cycloaddition of Triazenes with Alkynes and Their Deprotonative Functionalization. ASIAN J ORG CHEM 2021. [DOI: 10.1002/ajoc.202100033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Daiki Sawaguchi
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Shunsuke Hayakawa
- Department of Applied Chemistry Graduate School of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Masaaki Sakuma
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Kenta Niitsuma
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Daiya Kase
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Shota Michii
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Miyuki Ozawa
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Yusuke Sakai
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Kentaro Sakamaki
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Kyohei Ueyama
- Department of Applied Chemistry Graduate School of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
| | - Ryosuke Haraguchi
- Department of Applied Chemistry Faculty of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
- Department of Applied Chemistry Graduate School of Engineering Chiba Institute of Technology 2-17-1 Tsudanuma Narashino, Chiba 275-0016 Japan
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8
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Synthesis, structural diversity, and applications of mesoionic 1,2,3-triazol-5-ylidene metal complexes, an update (2017–2020). Polyhedron 2021. [DOI: 10.1016/j.poly.2020.114935] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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9
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Haraguchi R, Yamazaki T, Torita K, Ito T, Fukuzawa SI. Planar-chiral ferrocene-based triazolylidene copper complexes: synthesis, characterization, and catalysis in asymmetric borylation of α,β-unsaturated ester. Dalton Trans 2020; 49:17578-17583. [PMID: 33231226 DOI: 10.1039/d0dt03213a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
1,2,3-Triazol-5-ylidenes have recently attracted considerable attention as versatile ligands because of their strong electron-donating properties and structural diversities. While some efforts have been devoted to the development of chiral triazolylidene-metal complexes, there is no example achieving asymmetric induction by base-metal complexes with triazolylidene ligands. Herein, we synthesized planar-chiral ferrocene-based triazolylidene copper complexes, which enabled the asymmetric borylation of methyl cinnamate with bis(pinacolato)diboron with good enantioselectivity.
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Affiliation(s)
- Ryosuke Haraguchi
- Department of Applied Chemistry, Faculty of Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan.
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10
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Mashabane TL, Ramollo GK, Kleinhans G, De Doncker S, Siangwata S, Fernandes MA, Lemmerer A, Smith GS, Bezuidenhout DI. Tunable Rh(I) Fischer carbene complexes for application in the hydroformylation of 1-octene. J Organomet Chem 2020. [DOI: 10.1016/j.jorganchem.2020.121341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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Škoch K, Vosáhlo P, Císařová I, Štěpnička P. Synthesis and characterisation of Pd(ii) and Au(i) complexes with mesoionic carbene ligands bearing phosphinoferrocene substituents and isomeric carbene moieites. Dalton Trans 2020; 49:1011-1021. [PMID: 31916562 DOI: 10.1039/c9dt04521j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
While numerous functional ligands combining phosphine and imidazole-2-ylidene (or imidazolin-2-ylidene) donor moieties have already been reported, the chemistry of the corresponding functional mesoionic carbenes (MIC) derived from 1,2,3-triazoles remains nearly untapped. This contribution describes the synthesis of two isomeric series of triazolium salts bearing 1'-(diphenylphosphino)ferrocenyl substituents by [3 + 2] cycloaddition of a P-protected phosphinoferrocene alkyne with azides, or alternatively of a P-protected phosphinoferrocene azide with terminal alkynes, and by subsequent methylation. These salts were used to synthesize structurally unique Pd(ii) complexes featuring a P,C-chelating triazolylidene carbene ligands and Au(i)-MIC complexes with free phosphine groups. The latter were further utilised to prepare Pd(ii)Au(i) heterometallic complexes containing bridging ferrocene phosphino-carbenes as structurally flexible, donor-unsymmetric metalloligands. In addition, the reactivity of the newly prepared, P-protected phosphinoferrocene alkyne Ph2PfcC[triple bond, length as m-dash]CH·BH3 (fc = ferrocene-1,1'-diyl) was investigated, and representatives from all reported compound classes were structurally characterised.
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Affiliation(s)
- Karel Škoch
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Petr Vosáhlo
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
| | - Petr Štěpnička
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
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12
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Rhodium(I) metallacycles based on alkylated-PTA scaffolds: Synthesis and evaluation as hydroformylation catalyst precursors. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.119051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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Aucamp D, Kumar SV, Liles DC, Fernandes MA, Harmse L, Bezuidenhout DI. Synthesis of heterobimetallic gold(i) ferrocenyl-substituted 1,2,3-triazol-5-ylidene complexes as potential anticancer agents. Dalton Trans 2019; 47:16072-16081. [PMID: 30276400 DOI: 10.1039/c8dt03116a] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
1,2,3-Triazol-5-ylidene (trz) complexes of gold(i) containing a ferrocenyl substituent on the C4-position of the trz ring were synthesized to yield the neutral heterobimetallic gold(i) trz chlorido (2), gold(i) trz phenyl (3), and the cationic gold(i) trz triphenylphospine (5) complexes. In order to compare the effect of silver(i) as central metal vs. gold(i), [Ag(trz)2]+ (4) was also prepared, while variation of the C4-1,2,3-triazol-5-ylidene substituent from a ferrocenyl to a phenyl group was done to prepare the monometallic analogue of 5, namely the cationic Au(i) trz triphenylphosphine complex 6. The complexes were characterised with spectroscopic and electrochemical methods, and the single crystal X-ray structures of 2-6 were determined. NMR stability studies of 5 as a representative example of the series of complexes were performed to confirm the stability of the complexes in the solvent dimethylsulfoxide and in aqueous solution. The anti-cancer potential of 5 was evaluated against the lung cancer cell lines A549 and H1975, and the human embryonic kidney cell line (HEK-293) was used as a non-cancer model. IC50 values of 0.89, 0.23 and 5.43 μM, respectively, were obtained for A549, H1975 and HEK-293, respectively, indicating the activity and selectivity of 5 for cancer cells. Fluorescence microscopy experiments as a preliminary mode-of-action study evidenced an apoptotic cell death mechanism rather than necrotic cell death.
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Affiliation(s)
- Danielle Aucamp
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa.
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14
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Baltrun M, Watt FA, Schoch R, Wölper C, Neuba AG, Hohloch S. A new bis-phenolate mesoionic carbene ligand for early transition metal chemistry. Dalton Trans 2019; 48:14611-14625. [DOI: 10.1039/c9dt03099a] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A new chelating mesoionic carbene ligand, derived from 1,2,3-triazoles, with two redox-active tert-butyl-phenolate linkers has been synthesized and explored towards its reactivity and electrochemical properties in early transition metal chemistry.
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Affiliation(s)
- Marc Baltrun
- Universität Paderborn
- Fakultät für Naturwissenschaften
- Department Chemie Warburger Straße 100
- 33098 Paderborn
- Germany
| | - Fabian A. Watt
- Universität Paderborn
- Fakultät für Naturwissenschaften
- Department Chemie Warburger Straße 100
- 33098 Paderborn
- Germany
| | - Roland Schoch
- Universität Paderborn
- Fakultät für Naturwissenschaften
- Department Chemie Warburger Straße 100
- 33098 Paderborn
- Germany
| | | | - Adam G. Neuba
- Universität Paderborn
- Fakultät für Naturwissenschaften
- Department Chemie Warburger Straße 100
- 33098 Paderborn
- Germany
| | - Stephan Hohloch
- Universität Paderborn
- Fakultät für Naturwissenschaften
- Department Chemie Warburger Straße 100
- 33098 Paderborn
- Germany
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15
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Synthesis of Rh(I) alkylated-PTA complexes as catalyst precursors in the aqueous-biphasic hydroformylation of 1-octene. J Organomet Chem 2018. [DOI: 10.1016/j.jorganchem.2018.05.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Vivancos Á, Segarra C, Albrecht M. Mesoionic and Related Less Heteroatom-Stabilized N-Heterocyclic Carbene Complexes: Synthesis, Catalysis, and Other Applications. Chem Rev 2018; 118:9493-9586. [PMID: 30014699 DOI: 10.1021/acs.chemrev.8b00148] [Citation(s) in RCA: 318] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mesoionic carbenes are a subclass of the family of N-heterocyclic carbenes that generally feature less heteroatom stabilization of the carbenic carbon and hence impart specific donor properties and reactivity schemes when coordinated to a transition metal. Therefore, mesoionic carbenes and their complexes have attracted considerable attention both from a fundamental point of view as well as for application in catalysis and beyond. As a follow-up of an earlier Chemical Reviews overview from 2009, the organometallic chemistry of N-heterocyclic carbenes with reduced heteroatom stabilization is compiled for the 2008-2017 period, including specifically the chemistry of complexes containing 1,2,3-triazolylidenes, 4-imidazolylidenes, and related 5-membered N-heterocyclic carbenes with reduced heteratom stabilization such as (is)oxazolylidenes, pyrrazolylidenes, and thiazolylidenes, as well as pyridylidenes as 6-membered N-heterocyclic carbenes with reduced heteroatom stabilization. For each ligand subclass, metalation strategies, electronic and steric properties, and applications, in particular, in metal-mediated catalysis, are compiled. Mesoionic carbenes demonstrate particularly high activity in (water) oxidation, hydrogen transfer reactions, and cyclization reactions. Unique features of these ligands are identified such as their dipolar structure, their specific donor properties, as well as stability aspects of the ligand and the complexes, which provides opportunities for further research.
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Affiliation(s)
- Ángela Vivancos
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3 , CH-3012 Bern , Switzerland.,Departamento de Química Inorgánica , Universidad de Murcia , Apartado 4021 , 30071 Murcia , Spain
| | - Candela Segarra
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3 , CH-3012 Bern , Switzerland.,Instituto de Tecnología Química , Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas , Avenida de los Naranjos s/n , 46022 Valencia , Spain
| | - Martin Albrecht
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3 , CH-3012 Bern , Switzerland
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17
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Marichev KO, Patil SA, Bugarin A. Recent advances in the synthesis, structural diversity, and applications of mesoionic 1,2,3-triazol-5-ylidene metal complexes. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.04.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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18
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Huynh HV. Electronic Properties of N-Heterocyclic Carbenes and Their Experimental Determination. Chem Rev 2018; 118:9457-9492. [DOI: 10.1021/acs.chemrev.8b00067] [Citation(s) in RCA: 446] [Impact Index Per Article: 74.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Han Vinh Huynh
- Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore
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19
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Lamprecht Z, Radhakrishnan SG, Hildebrandt A, Lang H, Liles DC, Weststrate NA, Lotz S, Bezuidenhout DI. Mono-, di- and tetrarhenium Fischer carbene complexes with thienothiophene substituents. Dalton Trans 2017; 46:13983-13993. [PMID: 28975955 DOI: 10.1039/c7dt02969a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The oxidative cleaving of a rhenium-rhenium bond by bromine in binuclear Fischer carbene complexes proves to be an effective method to prepare mononuclear bromido-carbene complexes. The reaction of mono- and dilithiated thieno[2,3-b]thiophene (2,3-b-TTH2) and thieno[3,2-b]thiophene (3,2-b-TTH2) with [Re2(CO)10] affords dirhenium nonacarbonyl ethoxycarbene complexes, [Re2(CO)9{C(OEt)2,3-b-TTH}] (1a) and [Re2(CO)9{C(OEt)3,2-b-TTH}] (1b), and the tetrarhenium bis(ethoxycarbene) complexes from the dilithiated thiophene substrates, [Re2(CO)9-μ-{C(OEt)-2,3-b-TT-C(OEt)}Re2(CO)9] (2a) and [Re2(CO)9-μ-{C(OEt)-3,2-b-TT-C(OEt)}Re2(CO)9] (2b) featuring bridging thiophene linkers. Rhenium-rhenium bond cleavage by bromine of the monocarbene complexes yielded the scarce class of monorhenium bromido-carbene complexes, cis-[Re(CO)4{C(OEt)2,3-b-TTH}Br] (3a) and cis-[Re(CO)4{C(OEt)3,2-b-TTH}Br] (3b), while the corresponding reaction of the biscarbene tetrarhenium carbonyl complex of thieno[2,3-b]thiophene afforded the cleaving of both metal-metal bonds to give the novel dirhenium biscarbene dibromido complex with a thienothiophene spacer, [Re(CO)4Br-μ-{C(OEt)-2,3-b-TT-C(OEt)}Re(CO)4Br] (4a). A new indirect aminolysis route is described to prepare the chlorido dimethylaminocarbene complex 5acis-[Re(CO)4{C(NMe2)2,3-b-TTH}Cl], with unexpected cleavage of the Re-Re bond. Single crystal X-ray diffraction studies were performed on 1a, 2a, 3a, 5a, 1b and 3b. Spectroscopic and electrochemical methods are employed to investigate the electronic effect of the different conjugation pathways in the different thienothiophenyl carbene substituents, and the replacement of the rhenium pentacarbonyl fragment with a bromido ligand.
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Affiliation(s)
- Zandria Lamprecht
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa.
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