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Gu Q, Gorgon S, Romanov AS, Li F, Friend RH, Evans EW. Fast Transfer of Triplet to Doublet Excitons from Organometallic Host to Organic Radical Semiconductors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2402790. [PMID: 38819637 DOI: 10.1002/adma.202402790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 05/09/2024] [Indexed: 06/01/2024]
Abstract
Spin triplet exciton formation sets limits on technologies using organic semiconductors that are confined to singlet-triplet photophysics. In contrast, excitations in the spin doublet manifold in organic radical semiconductors can show efficient luminescence. Here the dynamics of the spin allowed process of intermolecular energy transfer from triplet to doublet excitons are explored. A carbene-metal-amide (CMA-CF3) is employed as a model triplet donor host, since following photoexcitation it undergoes extremely fast intersystem crossing to generate a population of triplet excitons within 4 ps. This enables a foundational study for tracking energy transfer from triplets to a model radical semiconductor, TTM-3PCz. Over 74% of all radical luminescence originates from the triplet channel in this system under photoexcitation. It is found that intermolecular triplet-to-doublet energy transfer can occur directly and rapidly, with 12% of triplet excitons transferring already on sub-ns timescales. This enhanced triplet harvesting mechanism is utilized in efficient near-infrared organic light-emitting diodes, which can be extended to other opto-electronic and -spintronic technologies by radical-based spin control in molecular semiconductors.
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Affiliation(s)
- Qinying Gu
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
- Shanghai Artificial Intelligence Laboratory, Shanghai, 200232, P. R. China
| | - Sebastian Gorgon
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Alexander S Romanov
- Department of Chemistry, University of Manchester, Oxford Rd., Manchester, M13 9PL, UK
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Avenue 2699, Changchun, 130012, P. R. China
| | - Richard H Friend
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Emrys W Evans
- Department of Chemistry, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
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Scattolin T, Tonon G, Botter E, Guillet SG, Tzouras NV, Nolan SP. Gold(I)-N-Heterocyclic Carbene Synthons in Organometallic Synthesis. Chemistry 2023; 29:e202301961. [PMID: 37463071 DOI: 10.1002/chem.202301961] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 07/20/2023]
Abstract
The prominent role of gold-N-heterocyclic carbene (NHC) complexes in numerous research areas such as homogeneous (photo)catalysis, medicinal chemistry and materials science has prompted organometallic chemists to design gold-based synthons that permit access to target complexes through simple synthetic steps under mild conditions. In this review, the main gold-NHC synthons employed in organometallic synthesis are discussed. Mechanistic aspects involved in their synthesis and reactivity as well as applications of gold-NHC synthons as efficient pre-catalysts, antitumor agents and/or photo-emissive materials are presented.
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Affiliation(s)
- Thomas Scattolin
- Dipartimento di Scienze Chimiche, Università degli studi di Padova, via Marzolo 1, 35131, Padova, Italy
| | - Giovanni Tonon
- Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari Campus Scientifico, Via Torino 155, 30174, Venezia-Mestre, Italy
| | - Eleonora Botter
- Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari Campus Scientifico, Via Torino 155, 30174, Venezia-Mestre, Italy
| | - Sebastien G Guillet
- Department of Chemistry and Centre for Sustainable Chemistry, Ghent University, Krijgslaan 281, S-3, 9000, Ghent, Belgium
| | - Nikolaos V Tzouras
- Department of Chemistry and Centre for Sustainable Chemistry, Ghent University, Krijgslaan 281, S-3, 9000, Ghent, Belgium
| | - Steven P Nolan
- Department of Chemistry and Centre for Sustainable Chemistry, Ghent University, Krijgslaan 281, S-3, 9000, Ghent, Belgium
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Amouri H. Luminescent Complexes of Platinum, Iridium, and Coinage Metals Containing N-Heterocyclic Carbene Ligands: Design, Structural Diversity, and Photophysical Properties. Chem Rev 2023; 123:230-270. [PMID: 36315851 DOI: 10.1021/acs.chemrev.2c00206] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The employment of N-heterocyclic carbenes (NHCs) to design luminescent metal compounds has been the focus of recent intense investigations because of the strong σ-donor properties, which bring stability to the whole system and tend to push the d-d dark states so high in energy that they are rendered thermally inaccessible, thereby generating highly emissive complexes for useful applications such as organic light-emitting diodes (OLEDs), or featuring chiroptical properties, a field that is still in its infancy. Among the NHC complexes, those containing organic chromophores such as naphthalimide, pyrene, and carbazole exhibit rich emission behavior and thus have attracted extensive interest in the past five years, especially carbene coinage metal complexes with carbazolate ligands. In this review, the design strategies of NHC-based luminescent platinum and iridium complexes with large spin-orbit-coupling (SOC) are described first. Subsequent paragraphs illustrate the recent advances of luminescent coinage metal complexes with nucleophilic- and electrophilic-based carbenes based on silver, gold, and copper metal complexes that have the ability to display rich excited state emissions in particular via thermally activated delayed fluorescence (TADF). The luminescence mechanism and excited state dynamics are also described. We then summarize the advance of NHC-metal complexes in the aforementioned fields in recent years. Finally, we propose the development trend of this fast-growing field of luminescent NHC-metal complexes.
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Affiliation(s)
- Hani Amouri
- CNRS, IPCM (UMR 8232), Sorbonne Université-Faculté des Sciences et Ingénerie Campus Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris, Cedex 05, France
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Liu HY, Neale SE, Hill MS, Mahon MF, McMullin CL. On the reactivity of Al-group 11 (Cu, Ag, Au) bonds. Dalton Trans 2022; 51:3913-3924. [PMID: 35169824 DOI: 10.1039/d2dt00404f] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Reactions of the seven-membered heterocyclic potassium diamidoalumanyl, [K{Al(SiNDipp)}]2 (SiNDipp = {CH2SiMe2NDipp}2; Dipp = 2,6-di-isopropylphenyl), with a variety of Cu(I), Ag(I) and Au(I) chloride N-heterocyclic carbene (NHC) adducts are described. The resultant group 11-Al bonded derivatives have been characterised in solution by NMR spectroscopy and, in the case of [{SiNDipp}Al-Au(NHCiPr)] (NHCiPr = N,N'-di-isopropyl-4,5-dimethyl-2-ylidene), by single crystal X-ray diffraction. Although similar reactions of LAgCl and LAuCl, where L is a more basic cyclic alkyl amino carbene (CAAC), generally resulted in reduction of the group 11 cations to the base metals, X-ray analysis of [(CyCAAC)AgAl(SiNDipp)] (CyCAAC = 2-[2,6-bis(1-methylethyl)phenyl]-3,3-dimethyl-2-azaspiro[4.5]dec-1-ylidene) provides the first solid-state authentication of an Ag-Al σ bond. The reactivity of the NHC-supported Cu, Ag and Au alumanyl derivatives was assayed with the isoelectronic unsaturated small molecules, N,N'-di-isopropylcarbodiimide and CO2. While these reactions generally provided products consistent with nucleophilic attack of the group 11 atom at the electrophilic heteroallene carbon centre, treatment of the NHC-supported copper and silver alumanyls with N,N'-di-isopropylcarbodiimide yielded less symmetric Cu-C and Ag-C-bonded isomers. In contrast to the previously described copper and silver alumanyl derivatives, [(NON)Al(O2C)M(Pt-Bu3)] (M = Cu or Ag; NON = 4,5-bis(2,6-di-isopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene), which were prone to facile CO extrusion and formation of carbonate derivatives, the NHC-supported dioxocarbene species, [(NHCiPr)M(CO2)Al(SiNDipp)] (M = Cu, Ag, Au), are all stable at room and moderately elevated temperatures. The stabilising role of the NHC co-ligand was, thus, assessed by preparation of the t-Bu3P adducted copper-alumanyl, [(t-Bu3P)CuAl(SiNDipp)]. Treatment of this latter compound, which was also structurally characterised by X-ray analysis, with both N,N'-di-isopropylcarbodiimide and CO2 again provided smooth heteroallene insertion and formation of the relevant Cu-C-bonded products. Although both compounds were quite stable at room temperature, heating of [(t-Bu3P)Cu(CO2)Al(SiNDipp)] at 60 °C induced elimination of CO and formation of the analogous carbonate, [(t-Bu3P)Cu(OCO2)Al(SiNDipp)], which was identified by 13C and 31P NMR spectroscopy. Reflective of the more reliable nucleophilic behaviour of the gold centres in these group 11 alumanyls, computational (QTAIM and NBO) analysis highlighted a lower level of covalency of the Al-Au linkage in comparison to the analogous Al-Cu and Al-Ag interactions. Although substitution of the co-ligand significantly perturbs the charge distribution across the Cu-Al bond of [LCuAl(SiNDipp)] (L = NHCiPr or t-Bu3P), only a negligible difference is observed between the phosphine-coordinated copper systems derived from either the [SiNDipp]- or (NON)-based alumanyl ligands. Computational mapping of the reaction profiles arising from treatment of the various group 11 alumanyls with N,N'-di-isopropylcarbodiimide indicates that the observed formation of the Cu-N and Ag-N bound isomers do not provide the thermodynamic reaction outcome. In contrast, examination of the CO2-derived reactions, and their potential toward CO extrusion and subsequent carbonate formation, implies that the identity of the co-ligand exerts a greater influence on this aspect of reactivity than the architecture of the diamidoalumanyl anion.
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Affiliation(s)
- Han-Ying Liu
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Samuel E Neale
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Michael S Hill
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Mary F Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Claire L McMullin
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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Roesky HW, Kushvaha SK, Mishra A, Mondal KC. Recent advances in the domain of Cyclic (alkyl)(amino) carbenes. Chem Asian J 2022; 17:e202101301. [PMID: 34989475 PMCID: PMC9307053 DOI: 10.1002/asia.202101301] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/25/2021] [Indexed: 12/03/2022]
Abstract
Isolation of cyclic (alkyl) amino carbenes (cAACs) in 2005 has been a major achievement in the field of stable carbenes due to their better electronic properties. cAACs and bicyclic(alkyl)(amino)carbene (BicAAC) in essence are the most electrophilic as well as nucleophilic carbenes are known till date. Due to their excellent electronic properties in terms of nucleophilic and electrophilic character, cAACs have been utilized in different areas of chemistry, including stabilization of low valent main group and transition metal species, activation of small molecules, and catalysis. The applications of cAACs in catalysis have opened up new avenues of research in the field of cAAC chemistry. This review summarizes the major results of cAAC chemistry published until August 2021.
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Affiliation(s)
- Herbert W Roesky
- Georg-August-Universitat Gottingen, Department of Chemistry, Tammannstrasse 4, 37077, Göttingen, GERMANY
| | | | - Ankush Mishra
- IIT Madras: Indian Institute of Technology Madras, Chemistry, INDIA
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Hölzel T, Belyaev A, Terzi M, Stenzel L, Gernert M, Marian CM, Steffen A, Ganter C. Linear Carbene Pyridine Copper Complexes with Sterically Demanding N, N'-Bis(trityl)imidazolylidene: Syntheses, Molecular Structures, and Photophysical Properties. Inorg Chem 2021; 60:18529-18543. [PMID: 34793149 DOI: 10.1021/acs.inorgchem.1c03082] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The sterically demanding carbene ITr (N,N'-bis(triphenylmethyl)imidazolylidene) was used as a ligand for the preparation of luminescent copper(I) complexes of the type [(ITr)Cu(R-pyridine/R'-quinoline)]BF4 (R = H, 4-CN, 4-CHO, 2,6-NH2, and R' = 8-Cl, 6-Me). The selective formation of linear, bis(coordinated) complexes was observed for a series of pyridine and quinoline derivatives. Only in the case of 4-cyanopyridine a one-dimensional coordination polymer was formed, in which the cyano group of the cyanopyridine ligand additionally binds to another Cu atom in a bridging manner, thus leading to a trigonal planar coordination environment. In contrast, employing sterically less demanding monotrityl-substituted carbene 3, no (NHC)Cu-pyridine complexes could be prepared. Instead, a bis-carbene complex [(3)2Cu]PF6 was obtained which showed no luminescence. All linear pyridine/quinoline coordinated complexes show weak emission in solution but intense blue to orange luminescence doped with 10% in PMMA films and in the solid state either from triplet excited states with unusually long lifetimes of up to 4.8 ms or via TADF with high radiative rate constants of up to 1.7 × 105 s-1 at room temperature. Combined density functional theory and multireference configuration interaction calculations have been performed to rationalize the involved photophysics of these complexes. They reveal a high density of low-lying electronic states with mixed MLCT, LLCT, and LC character where the electronic structures of the absorbing and emitting state are not necessarily identical.
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Affiliation(s)
- Torsten Hölzel
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Andrey Belyaev
- Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany
| | - Meryem Terzi
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Laura Stenzel
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Markus Gernert
- Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany
| | - Christel M Marian
- Institut für Theoretische Chemie und Computerchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Andreas Steffen
- Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany
| | - Christian Ganter
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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Romanov AS, Linnolahti M, Bochmann M. Synthesis and photophysical properties of linear gold(I) complexes based on a CCC carbene. Dalton Trans 2021; 50:17156-17164. [PMID: 34781337 PMCID: PMC8631002 DOI: 10.1039/d1dt03393j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction between allenylpyridine (L1) and (Me2S)AuCl resulted in the quantitative formation of the (Indolizy)gold chloride complex 1 (Indolizy = indolizin-2-ylidene). The reaction of 1 with carbazole in the presence of KOtBu affords the corresponding (Indolizy)Au(Cz) complex 2. Both compounds show high air- and temperature stability. The crystal structure of 2 confirmed the linear co-planar geometry. Complex 1 shows an intense low energy absorption of mixed character in the UV-vis spectrum, ascribed to intraligand and (M + Hal)L charge transfer processes, and exhibits bright yellow phosphorescence with an excited state lifetime of 62.8 μs in the crystal and a luminescence quantum yield up to 65%. On the other hand, the carbazolate complex 2 in a polystyrene matrix shows bright red delayed fluorescence at 617 nm with a sub-microsecond excited state lifetime and a quantum yield of 21.6%.
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Affiliation(s)
- Alexander S Romanov
- School of Chemistry, University of East Anglia, Earlham Road, Norwich, NR4 7TJ, UK. .,School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, FI-80101 Joensuu, Finland.
| | - Manfred Bochmann
- School of Chemistry, University of East Anglia, Earlham Road, Norwich, NR4 7TJ, UK.
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Lüdtke N, Föller J, Marian CM. Understanding the luminescence properties of Cu(i) complexes: a quantum chemical perusal. Phys Chem Chem Phys 2020; 22:23530-23544. [PMID: 33074271 DOI: 10.1039/d0cp04654j] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Electronic structures and excited-state properties of Cu(i) complexes with varying coordination numbers have been investigated by means of advanced quantum chemical methods. The computational protocol employs density functional-based methods for geometry optimizations and vibrational analyses including solvent effects through continuum models. Excitation energies, spin-orbit couplings and luminescence properties are evaluated using multireference configuration interaction methods. Rate constants of spin-allowed and spin-forbidden transitions have been determined according to the Fermi golden rule. The computational results for the 4-coordinate (DPEPhos)Cu(PyrTet), the 3-coordinate [IPr-Cu-Py2]+, and the linear CAACMe2-Cu-Cl complexes agree well with experimental absorption and emission wavelengths, intersystem crossing (ISC) time constants, and radiative lifetimes in liquid solution. Spectral shifts on the ligand-to-ligand charge transfer (LLCT) and metal-to-ligand charge transfer (MLCT) transitions caused by the polarity of the environment are well represented by the continuum models whereas the shifts caused by pseudo-Jahn-Teller distortions in the MLCT states are too pronounced in comparison to solid-state data. Systematic variation of the ligands in linear Cu(i) carbene complexes shows that only those complexes with S1 and T1 states of LLCT character possess sufficiently small singlet-triplet energy gaps ΔEST to enable thermally activated delayed fluorescence (TADF). Complexes whose S1 and T1 wavefunctions are dominated by MLCT excitations tend to emit phosphorescence instead. Unlike the situation in metal-free TADF emitters, the presence of low-lying locally excited triplet states does not promote ISC. These states rather hold the danger of trapping the excitation with nonradiative deactivation being the major deactivation channel.
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Affiliation(s)
- Nora Lüdtke
- Institute of Theoretical and Computational Chemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| | - Jelena Föller
- Institute of Theoretical and Computational Chemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| | - Christel M Marian
- Institute of Theoretical and Computational Chemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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Mercury(II) Complexes of Anionic N-Heterocyclic Carbene Ligands: Steric Effects of the Backbone Substituent. Molecules 2020; 25:molecules25163741. [PMID: 32824333 PMCID: PMC7464600 DOI: 10.3390/molecules25163741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 01/24/2023] Open
Abstract
Mercury(II) complexes (Me-maloNHCDipp)HgCl (1b), (t-Bu-maloNHCDipp)HgCl (2b) and (t-Bu-maloNHCDipp)HgMe (2c) supported by anionic N-heterocyclic carbenes have been obtained in good yields from the reaction of the potassium salt of N-heterocyclic carbene ligand precursors and mercury(II) salts, HgCl2 and MeHgI. These molecules have been characterized by 1H-NMR, 13C-NMR and IR spectroscopy and elemental analysis. X-ray crystal structures of 1b and 2b are also presented. Interestingly, complex 1b is polymeric {(Me-maloNHCDipp)HgCl}n in the solid state, as a result of inter-molecular Hg-O contacts, and features rare three coordinate mercury sites with a T-shaped arrangement, whereas the (t-Bu-maloNHCDipp)HgCl (2b) is monomeric and has a linear, two-coordinate mercury center. The formation of T-shaped structure and the aggregation of complex 1b is attributable to the reduced steric demand of the N-heterocyclic carbene ligand backbone substituent.
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Jazzar R, Soleilhavoup M, Bertrand G. Cyclic (Alkyl)- and (Aryl)-(amino)carbene Coinage Metal Complexes and Their Applications. Chem Rev 2020; 120:4141-4168. [DOI: 10.1021/acs.chemrev.0c00043] [Citation(s) in RCA: 131] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Rodolphe Jazzar
- UCSD-CNRS Joint Research Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States
| | - Michele Soleilhavoup
- UCSD-CNRS Joint Research Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States
| | - Guy Bertrand
- UCSD-CNRS Joint Research Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States
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