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McEllin A, Goult CA, Mohiuddin G, Curtis LJ, Tanner TFN, Whitwood AC, Lynam JM, Bruce DW. Gold(III), Mercury(II), and Palladium(II) Complexes of a Series of Isomeric Bis(mono- and dialkoxyphenyl)pyridines: Introduction of Gold through Transmetalation and Catalysis. Inorg Chem 2024; 63:7589-7603. [PMID: 38635870 PMCID: PMC11061838 DOI: 10.1021/acs.inorgchem.3c03791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 04/04/2024] [Accepted: 04/04/2024] [Indexed: 04/20/2024]
Abstract
A series of isomeric bis-2,6-(monoalkoxyphenyl)pyridine and bis-2,6-(dialkoxyphenyl)pyridine ligands were synthesized and characterized. In order to prepare their chlorogold(III) complexes, intermediate chloromercury(II) complexes were first prepared, but unlike observations from previous studies where they were obtained impure and at best in moderate yield, here pure complexes were synthesized, many in rather high yields. Depending on the substitution pattern of the alkoxy chains on the ligands, mono- and/or dimercurated complexes were obtained, characterized by 1H, 13C{1H}, and 199Hg NMR spectroscopy as well as, in several cases, by X-ray crystallography. Factors that may explain this unusual reactivity are discussed. In most cases, transmetalation to the related chlorogold(III) complex proceeded smoothly, although lower yields were obtained when starting from doubly mercurated precursors. Prompted by the propensity of these ligands to mercurate, attempts were made to effect direct auration, but none was successful. However, dimeric, orthometalated complexes of palladium(II) could be prepared and were also amenable to transmetalation to the chlorogold(III) complex, providing for a mercury-free synthesis.
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Affiliation(s)
- Alice
Jane McEllin
- Department
of Chemistry, University of York Heslington, YORK YO10 5DD, U.K.
| | | | - Golam Mohiuddin
- Department
of Chemistry, University of York Heslington, YORK YO10 5DD, U.K.
- Department
of Chemistry, University of Science &
Technology Meghalaya, Ri-Bhoi, Meghalaya 793101, India
| | - Liam J. Curtis
- Department
of Chemistry, University of York Heslington, YORK YO10 5DD, U.K.
| | - Theo F. N. Tanner
- Department
of Chemistry, University of York Heslington, YORK YO10 5DD, U.K.
| | - Adrian C. Whitwood
- Department
of Chemistry, University of York Heslington, YORK YO10 5DD, U.K.
| | - Jason M. Lynam
- Department
of Chemistry, University of York Heslington, YORK YO10 5DD, U.K.
| | - Duncan W. Bruce
- Department
of Chemistry, University of York Heslington, YORK YO10 5DD, U.K.
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Holmsen MSM, Nova A, Tilset M. Cyclometalated (N,C) Au(III) Complexes: The Impact of Trans Effects on Their Synthesis, Structure, and Reactivity. Acc Chem Res 2023; 56:3654-3664. [PMID: 38051910 PMCID: PMC10734256 DOI: 10.1021/acs.accounts.3c00595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 12/07/2023]
Abstract
ConspectusThe early years of gold catalysis were dominated by Au(I) complexes and inorganic Au(III) salts. Thanks to the development of chelating ligands, more sophisticated Au(III) complexes can now be easily prepared and handled. The choice of the ancillary ligand has great consequences for the synthesis, properties, and reactivity of the Au(III) complex in question. Among the major factors controlling reactivity are the "trans effect" and the "trans influence" that a ligand imparts at the ligand trans to itself. The kinetic trans effect manifests itself with an increased labilization of the ligand trans to a given ligand and arises from an interplay between ground-state and transition-state effects. The term trans influence, on the other hand, is a ground-state effect only, describing the tendency of a given ligand to weaken the metal-ligand bond trans to itself. Herein, we will use the term "trans effect" to describe both the kinetic and the thermodynamic properties, whereas the term "trans influence" will refer only to thermodynamic properties. We will describe how these trans effects strongly impact the chemistry of the commonly encountered cyclometalated (N,C) Au(III) complexes, a class of complexes we have studied for more than a decade. We found that the outcome of reactions like alkylation, arylation, and alkynylation as well as halide metathesis are dictated by the different trans influence of the two termini of the chelating tpy ligand in (tpy)Au(OAcF)2 (tpy = 2-(p-tolyl)pyridine, OAcF = OCOCF3, tpy-C > tpy-N). There is a strong preference for high trans influence ligands to end up trans to tpy-N, whereas the lower trans influence ligands end up trans to tpy-C. Taking advantage of these preferences, tailor-made (N,C)Au(III) complexes could be prepared. For the functionalization of alkenes at (tpy)Au(OAcF)2, the higher trans effect of tpy-C would suggest that the coordination site trans to tpy-C would be kinetically more available than the one trans to tpy-N. However, due to the thermodynamic preference of having the σ-bonded ligand, resulting from the nucleophilic addition to alkenes, trans to tpy-N, functionalization of alkenes was only observed trans to tpy-N. However, for a catalytic process, the reaction should happen trans to tpy-C, as was observed for the trifluoroacetoxylation of acetylene. When functionalizing acetylene in the coordination site trans to tpy-N, protolytic cleavage of the Au-C(vinyl) bond to release the product did not occur at all, whereas trans to tpy-C protolytic cleavage of the Au-C(vinyl) bond occurred readily, in agreement with the higher trans influence of tpy-C over tpy-N. The large impact of the trans effects in Au(III) complexes is finally exemplified with the synthesis of [(tpy)Au(π-allyl)]+[NTf2]-, which resulted in a highly asymmetric π + σ bonding of the allyl moiety. Here, the bonding is such that the most thermodynamically favorable situation is achieved, with the carbon trans to tpy-N bonded in a σ-fashion and the π-allyl double bond being coordinated trans to tpy-C.
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Affiliation(s)
- Marte Sofie Martinsen Holmsen
- Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
- Centre
for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1126, Blindern, N-0316 Oslo, Norway
| | - Ainara Nova
- Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
- Centre
for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1126, Blindern, N-0316 Oslo, Norway
- Hylleraas
Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
- UiT-The
Arctic University of Norway, N-9037 Tromsø, Norway
| | - Mats Tilset
- Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
- Centre
for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1126, Blindern, N-0316 Oslo, Norway
- Hylleraas
Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
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Au(III) Cyclometallated Compounds with 2-Arylpyridines and Their Derivatives or Analogues: 34 Years (1989–2022) of NMR and Single Crystal X-ray Studies. INORGANICS 2023. [DOI: 10.3390/inorganics11030100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
A review paper on Au(III) cyclometallated compounds with 2-arylpyridines (2-phenylpyridine, 2-benzylpyridine, 2-benzoylpyridine, 2-phenoxypyridine, 2-phenylsulfanylpyridine, 2-anilinopyridine, 2-(naphth-2-yl)pyridine, 2-(9,9-dialkylfluoren-2-yl)pyridines, 2-(dibenzofuran-4-yl)pyridine, and their derivatives) and their analogues (2-arylquinolines, 1- and 3-arylisoquinolines, 7,8-benzoquinoline), with 113 references. A total of 554 species, containing κ2-N(1),C(6′)*-Au(III), or analogous moiety (i.e., chelated by nitrogen of the pyridine-like ring and the deprotonated ortho- carbon of the phenyl-like ring) and, thus, possessing a character intermediate between metal complexes and organometallics, studied in the years 1989–2022 by NMR spectroscopy and/or single crystal X-ray diffraction (207 X-ray structures), are described. The compounds for which biological or catalytic activity and the luminescence properties were studied are also quoted.
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McEllin AJ, Goult CA, Whitwood AC, Lynam JM, Bruce DW. On the mercuration, palladation, transmetalation and direct auration of a C^N^C pincer ligand. Dalton Trans 2023; 52:872-876. [PMID: 36632828 DOI: 10.1039/d2dt04114f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The C^N^C ligand 2,6-bis(2,3-dialkoxyphenyl)pyridine forms dimercury and orthopalladated complexes, both of which may be transmetallated to gold(III) complexes; the gold complexes may also be formed directly in a Rh(III)-catalysed process, hence it is possible to circumvent the use of organomercury intermediates in the synthesis of this important class of compound.
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Affiliation(s)
- Alice Jane McEllin
- Department of Chemistry, University of York, Heslington, YORK YO10 5DD, UK.
| | | | - Adrian C Whitwood
- Department of Chemistry, University of York, Heslington, YORK YO10 5DD, UK.
| | - Jason M Lynam
- Department of Chemistry, University of York, Heslington, YORK YO10 5DD, UK.
| | - Duncan W Bruce
- Department of Chemistry, University of York, Heslington, YORK YO10 5DD, UK.
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Holmsen MSM, Blons C, Amgoune A, Regnacq M, Lesage D, Sosa Carrizo ED, Lavedan P, Gimbert Y, Miqueu K, Bourissou D. Mechanism of Alkyne Hydroarylation Catalyzed by (P,C)-Cyclometalated Au(III) Complexes. J Am Chem Soc 2022; 144:22722-22733. [PMID: 36455211 DOI: 10.1021/jacs.2c10737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Over the last 5-10 years, gold(III) catalysis has developed rapidly. It often shows complementary if not unique features compared to gold(I) catalysis. While recent work has enabled major synthetic progress in terms of scope and efficiency, very little is yet known about the mechanism of Au(III)-catalyzed transformations and the relevant key intermediates have rarely been authenticated. Here, we report a detailed experimental/computational mechanistic study of the recently reported intermolecular hydroarylation of alkynes catalyzed by (P,C)-cyclometalated Au(III) complexes. The cationic (P,C)Au(OAcF)+ complex (OAcF = OCOCF3) was authenticated by mass spectrometry (MS) in the gas phase and multi-nuclear NMR spectroscopy in solution at low temperatures. According to density functional theory (DFT) calculations, the OAcF moiety is κ2-coordinated to gold in the ground state, but the corresponding κ1-forms featuring a vacant coordination site sit only slightly higher in energy. Side-on coordination of the alkyne to Au(III) then promotes nucleophilic addition of the arene. The energy profiles for the reaction between trimethoxybenzene (TMB) and diphenylacetylene (DPA) were computed by DFT. The activation barrier is significantly lower for the outer-sphere pathway than for the alternative inner-sphere mechanism involving C-H activation of the arene followed by migratory insertion. The π-complex of DPA was characterized by MS. An unprecedented σ-arene Au(III) complex with TMB was also authenticated both in the gas phase and in solution. The cationic complexes [(P,C)Au(OAcF)]+ and [(P,C)Au(OAcF)(σ-TMB)]+ stand as active species and off-cycle resting state during catalysis, respectively. This study provides a rational basis for the further development of Au(III) catalysis based on π-activation.
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Affiliation(s)
- Marte Sofie Martinsen Holmsen
- Laboratoire Hétérochimie Fondamentale et Appliquée - LHFA UMR 5069, CNRS/Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 09, France.,Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1126 Blindern, N-0316 Oslo, Norway.,Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway
| | - Charlie Blons
- Laboratoire Hétérochimie Fondamentale et Appliquée - LHFA UMR 5069, CNRS/Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 09, France
| | - Abderrahmane Amgoune
- Laboratoire Hétérochimie Fondamentale et Appliquée - LHFA UMR 5069, CNRS/Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 09, France
| | - Matthieu Regnacq
- Institut Parisien de Chimie Moléculaire - IPCM UMR 8232, CNRS/Sorbonne Université, 4 Place Jussieu, CC 229, 75252 Paris Cedex 05, France
| | - Denis Lesage
- Institut Parisien de Chimie Moléculaire - IPCM UMR 8232, CNRS/Sorbonne Université, 4 Place Jussieu, CC 229, 75252 Paris Cedex 05, France
| | - E Daiann Sosa Carrizo
- CNRS/Université de Pau et des Pays de l'Adour, E2S-UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - IPREM UMR 5254, Hélioparc. 2 Avenue du Président Angot, 64053 Pau Cedex 09, France
| | - Pierre Lavedan
- Institut de Chimie de Toulouse - ICT, CNRS/Université de Toulouse, UPS, 118 Route de Narbonne, 31062 Toulouse Cedex 09, France
| | - Yves Gimbert
- Institut Parisien de Chimie Moléculaire - IPCM UMR 8232, CNRS/Sorbonne Université, 4 Place Jussieu, CC 229, 75252 Paris Cedex 05, France.,Département de Chimie Moléculaire - DCM UMR 5250, CNRS/Université Grenoble Alpes, UGA, 38000 Grenoble, France
| | - Karinne Miqueu
- CNRS/Université de Pau et des Pays de l'Adour, E2S-UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - IPREM UMR 5254, Hélioparc. 2 Avenue du Président Angot, 64053 Pau Cedex 09, France
| | - Didier Bourissou
- Laboratoire Hétérochimie Fondamentale et Appliquée - LHFA UMR 5069, CNRS/Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 09, France
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