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Vanston CR, Nicholls TP, Bissember AC, Gardiner MG, Ho CC. Cationic Charge-Appended Abnormal Carbenes: Synthesis and Study of Electronically Modified Abnormal N-Heterocyclic Carbenes. Inorg Chem 2021; 61:622-632. [PMID: 34941242 DOI: 10.1021/acs.inorgchem.1c03336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A range of palladium complexes featuring electronically modified, imidazole-based abnormal N-heterocyclic carbene (aNHC) ligands have been prepared in the hopes of accessing a new class of cationic aNHC ligands electronically distinct from normal NHCs and aNHCs. These palladium complexes represent the first examples of transition metal-ligated aNHC complexes featuring a cationic moiety adjacent to the abnormal carbene center. It was anticipated that these design principles could facilitate electron transfer between the imidazolinylidene and the cationic heterocycle, thus reducing the electron density at the abnormal carbene center. However, this case study suggests that greater conformational restrictions that allow for heterocycle coplanarity are necessary to achieve significant electron transfer and enable access to a new class of cationic charge-appended aNHCs with unique electronic properties.
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Affiliation(s)
- Catriona R Vanston
- School of Natural Sciences-Chemistry, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Thomas P Nicholls
- School of Natural Sciences-Chemistry, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Alex C Bissember
- School of Natural Sciences-Chemistry, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Michael G Gardiner
- School of Natural Sciences-Chemistry, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Curtis C Ho
- School of Natural Sciences-Chemistry, University of Tasmania, Hobart, Tasmania 7001, Australia
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2
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Valyaev DA, Canac Y. Carbenes and phosphonium ylides: a fruitful association in coordination chemistry. Dalton Trans 2021; 50:16434-16442. [PMID: 34664574 DOI: 10.1039/d1dt03155d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Among a plethora of σ-donor ligands available, carbon-centered ones have become essential, in particular with the emergence of N-heterocyclic carbenes (NHCs), positioning themselves as credible alternatives to traditional nitrogen- and phosphorus-based systems. Phosphonium ylides representing another class of neutral η1-bonded carbon ligands have also been shown to act as effective Lewis bases. Considering the intrinsic features of the carbene and phosphonium ylide ligands, similar in terms of electronic properties, but different in terms of bonding mode, the design of hybrid systems combining these two types of carbon functionalities appeared to be a natural and exciting challenge. This Perspective comprehensively covers the chemistry of such ligand architectures from synthesis and fundamental aspects to catalytic applications.
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Affiliation(s)
- Dmitry A Valyaev
- LCC-CNRS, Université de Toulouse, CNRS, UPS, Toulouse Cedex 4 31077, France.
| | - Yves Canac
- LCC-CNRS, Université de Toulouse, CNRS, UPS, Toulouse Cedex 4 31077, France.
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Zhan L, Zhu M, Liu L, Wang J, Xie C, Zhang J. Synthesis of MAuAg (M = Ni, Pd, or Pt) and NiAuCu Heterotrimetallic Complexes Ligated by a Tritopic Carbanionic N-Heterocyclic Carbene. Inorg Chem 2021; 60:16035-16041. [PMID: 34648263 DOI: 10.1021/acs.inorgchem.1c01964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Heterotrimetallic complexes (NiAuAg, PdAuAg, PtAuAg, and NiAuCu) containing a tritopic N-heterocyclic carbene (NHC) have been synthesized for the first time through the deprotonation and metalation of heterodimetallic complexes and were structurally characterized by single-crystal X-ray diffraction. The carbene character of the donor groups in the tritopic NHC complexes was established on the basis of structural and NMR analyses.
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Affiliation(s)
- Licheng Zhan
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Mingqiu Zhu
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Lin Liu
- School of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jiwei Wang
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Congyun Xie
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Jun Zhang
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
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Brousses R, Maurel V, Mouesca JM, César V, Lugan N, Valyaev DA. Half-sandwich manganese complexes Cp(CO) 2Mn(NHC) as redox-active organometallic fragments. Dalton Trans 2021; 50:14264-14272. [PMID: 34553709 DOI: 10.1039/d1dt02182f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Oxidation of the half-sandwich MnI complexes Cp(CO)2Mn(NHC) bearing dialkyl-, arylalkyl- and diarylsubstituted N-heterocyclic carbene ligands (NHC = IMe, IMeMes, IMes) affords the corresponding stable MnII radical cations [Cp(CO)2Mn(NHC)](BF4) isolated in 92-95% yield. Systematic X-ray diffraction studies of the series of MnI and MnII NHC complexes revealed the expected characteristic structural changes upon oxidation, namely the elongation of the Mn-CO and Mn-NHC bonds as well as the diminution of the OC-Mn-CO angle. ESR spectra of [Cp(CO)2Mn(IMes)](BF4) in frozen solution (CH2Cl2/toluene 1 : 1, 70 K) allowed the identification of two conformers for this complex and their structural assignment using DFT calculations. The stability of these NHC complexes in both metal oxidation states, moderate oxidation potentials and the ease of detection of MnII species by a variety of spectroscopic techniques (UV-Vis, IR, paramagnetic 1H NMR, and ESR) make these compounds promising objects for applications as redox-active organometallic fragments.
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Affiliation(s)
- Rémy Brousses
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, France.
| | - Vincent Maurel
- Univ. Grenoble Alpes, CEA, CNRS, INAC, SyMMES, F-38000 Grenoble, France.
| | - Jean-Marie Mouesca
- Univ. Grenoble Alpes, CEA, CNRS, INAC, SyMMES, F-38000 Grenoble, France.
| | - Vincent César
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, France.
| | - Noël Lugan
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, France.
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Poyatos M, Peris E. Insights into the past and future of Janus-di-N-heterocyclic carbenes. Dalton Trans 2021; 50:12748-12763. [PMID: 34581341 DOI: 10.1039/d1dt02035h] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Janus di-N-heterocyclic carbene (NHC) ligands are a subclass of poly-NHCs that feature coordination to two transition metals in a facially opposed manner. The combination of the structural features of Janus type ligands, with the properties conferred by the NHC ligands, has conferred Janus-di-NHCs with privileged attributes for their use in diverse areas of research, such as homogeneous catalysis, materials chemistry and supramolecular chemistry. In molecular chemistry, Janus di-NHCs constitute one of the most useful chemical platforms for constructing dimetallic structures, and this includes both homo- and hetero-dimetallic compounds. This review aims to cover the most relevant advances in the use of Janus-di-NHCs during the last 15 years, by classifying them according to their specific structural features.
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Affiliation(s)
- Macarena Poyatos
- Institute of Advanced Materials (INAM), Universitat Jaume I, Av. Vicente Sos Baynat s/n, Castellón, E-1271, Spain.
| | - Eduardo Peris
- Institute of Advanced Materials (INAM), Universitat Jaume I, Av. Vicente Sos Baynat s/n, Castellón, E-1271, Spain.
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Taakili R, Barthes C, Lepetit C, Duhayon C, Valyaev DA, Canac Y. Direct Access to Palladium(II) Complexes Based on Anionic C, C, C-Phosphonium Ylide Core Pincer Ligand. Inorg Chem 2021; 60:12116-12128. [PMID: 34333976 DOI: 10.1021/acs.inorgchem.1c01316] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction of readily available imidazolium-phosphonium salt [MesIm(CH2)3PPh3](OTf)2 with PdCl2 in the presence of an excess of Cs2CO3 afforded selectively in one step the cationic Pd(II) complex [(C,C,C)Pd(NCMe)](OTf) exhibiting an LX2-type NHC-ylide-aryl C,C,C-pincer ligand via formal triple C-H bond activation. The replacement of labile MeCN in the latter by CNtBu and CO fragments allowed to estimate the overall electronic properties of this phosphonium ylide core pincer scaffold incorporating three different carbon-based donor ends by IR spectroscopy, cyclic voltammetry, and molecular orbital analysis, revealing its significantly higher electron-rich character compared to the structurally close NHC core pincer system with two phosphonium ylide extremities. The pincer complex [(C,C,C)Pd(CO)](OTf) represents a rare example of Pd(II) carbonyl species stable at room temperature and characterized by X-ray diffraction analysis. The treatment of isostructural cationic complexes [(C,C,C)Pd(NCMe)](OTf) and [(C,C,C)Pd(CO)](OTf) with (allyl)MgBr and nBuLi led to the formation of zwitterionic phosphonium organopalladates [(C,C,C)PdBr] and [(C,C,C)Pd(COnBu)], respectively.
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Affiliation(s)
- Rachid Taakili
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Cedex 4 Toulouse, France
| | - Cécile Barthes
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Cedex 4 Toulouse, France
| | - Christine Lepetit
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Cedex 4 Toulouse, France
| | - Carine Duhayon
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Cedex 4 Toulouse, France
| | - Dmitry A Valyaev
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Cedex 4 Toulouse, France
| | - Yves Canac
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Cedex 4 Toulouse, France
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Termühlen S, Wilm LFB, Dutschke PD, Hepp A, Hahn FE. Synthesis of Heterobimetallic Complexes through Chemoselective 2,4-Metalation of a Thiazolium Salt. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00243] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Sebastian Termühlen
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - Lukas F. B. Wilm
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - Patrick D. Dutschke
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - Alexander Hepp
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - F. Ekkehardt Hahn
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
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