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Upmann D, Jones PG, Bockfeld D, Târcoveanu E. Crystal structures of sixteen phosphane chalcogenide complexes of gold(I) chloride, bromide and iodide. Acta Crystallogr E Crystallogr Commun 2024; 80:34-49. [PMID: 38312159 PMCID: PMC10833370 DOI: 10.1107/s2056989023010459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 12/05/2023] [Indexed: 02/06/2024]
Abstract
The structures of 16 phosphane chalcogenide complexes of gold(I) halides, with the general formula R 1 3- nR 2 nPEAuX (R 1 = t-butyl; R 2 = isopropyl; n = 0 to 3; E = S or Se; X = Cl, Br or I), are presented. The eight possible chlorido derivatives are: 1a, n = 3, E = S; 2a, n = 2, E = S; 3a, n = 1, E = S; 4a, n = 0, E = S; 5a, n = 3, E = Se; 6a, n = 2, E = Se; 7a, n = 1, E = Se; and 8a, n = 0, E = Se, and the corresponding bromido derivatives are 1b-8b in the same order. However, 2a and 2b were badly disordered and 8a was not obtained. The iodido derivatives are 2c, 6c and 7c (numbered as for the series a and b). All structures are solvent-free and all have Z' = 1 except for 6b and 6c (Z' = 2). All mol-ecules show the expected linear geometry at gold and approximately tetra-hedral angles P-E-Au. The presence of bulky ligands forces some short intra-molecular contacts, in particular H⋯Au and H⋯E. The Au-E bond lengths have a slight but consistent tendency to be longer when trans to a softer X ligand, and vice versa. The five compounds 1a, 5a, 6a, 1b and 5b form an isotypic set, despite the different alkyl groups in 6a. Compounds 3a/3b, 4b/8b and 6b/6c form isotypic pairs. The crystal packing can be analysed in terms of various types of secondary inter-actions, of which the most frequent are 'weak' hydrogen bonds from methine hydrogen atoms to the halogenido ligands. For the structure type 1a, H⋯X and H⋯E contacts combine to form a layer structure. For 3a/3b, the packing is almost featureless, but can be described in terms of a double-layer structure involving borderline H⋯Cl/Br and H⋯S contacts. In 4a and 4b/8b, which lack methine groups, Cmeth-yl-H⋯X contacts combine to form layer structures. In 7a/7b, short C-H⋯X inter-actions form chains of mol-ecules that are further linked by association of short Au⋯Se contacts to form a layer structure. The packing of compound 6b/6c can conveniently be analysed for each independent mol-ecule separately, because they occupy different regions of the cell. Mol-ecule 1 forms chains in which the mol-ecules are linked by a Cmethine⋯Au contact. The mol-ecules 2 associate via a short Se⋯Se contact and a short H⋯X contact to form a layer structure. The packing of compound 2c can be described in terms of two short Cmethine-H⋯I contacts, which combine to form a corrugated ribbon structure. Compound 7c is the only compound in this paper to feature Au⋯Au contacts, which lead to twofold-symmetric dimers. Apart from this, the packing is almost featureless, consisting of layers with only translation symmetry except for two very borderline Au⋯H contacts.
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Affiliation(s)
- Daniel Upmann
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany
| | - Peter G. Jones
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany
| | - Dirk Bockfeld
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany
| | - Eliza Târcoveanu
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany
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Michalak M, Czerwiński P, Śniady-Maciążek K, Musioł S, Danylyuk O, Wierzbicki M, Tomasini M, Poater A. Chiral NHC Ligands for Enantioselective Gold(I) Catalysis Under Aerobic Conditions: the Importance of Conformational Flexibility and Steric Hindrance of NHC Ligand on Reactivity. Chemistry 2023:e202303241. [PMID: 38126930 DOI: 10.1002/chem.202303241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/28/2023] [Accepted: 12/18/2023] [Indexed: 12/23/2023]
Abstract
Gold(I) catalysis has been recognized as a valuable tool for the unique transformation of multiple carbon-carbon bonds. Enantioselective π-catalysis based on gold(I) complexes is, however, still underdeveloped due to lack of privileged ligands. Herein, we present an accessible method to a new family of stable yet catalytically active chiral NHC-Au(I)-Cl complexes. The key to preserving a simultaneous fine balance between reactivity and stability in this newly developed family appears to be sterically hindered, but conformationally flexible NHC ligands. These could be easily accessed on a multigram scale by merging sterically hindered anilines with commercially available amino alcohols and amines via a four-steps synthetic sequence without the need for chromatographic purification. Further investigations of the catalytic activity of NHC-Au-Cl complexes identified the OH functionality incorporated into the NHC core as crucial for the level of enantioselectivity as well as the TsO- anion responsible for the activation of NHC-Au(I)-Cl. Finally, NMR studies and X-ray investigations revealed for the first time that the widely accepted ion metathesis (NHC-Au-Cl to NHC-Au-OSO2 R) responsible for the activation of NHC-Au-Cl complexes does not take place (or it is very slow) in commonly used MeNO2 in contrast to DCM.
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Affiliation(s)
- Michał Michalak
- Polish Academy of Sciences, Institute of Organic Chemistry, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Paweł Czerwiński
- Polish Academy of Sciences, Institute of Organic Chemistry, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | | | - Szymon Musioł
- Polish Academy of Sciences, Institute of Organic Chemistry, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Oksana Danylyuk
- Polish Academy of Sciences, Institute of Physical Chemistry, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Michał Wierzbicki
- Polish Academy of Sciences, Institute of Organic Chemistry, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Michele Tomasini
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, c/M. Aurèlia Capmany 69, 17003, Girona, Catalonia, Spain
| | - Albert Poater
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, c/M. Aurèlia Capmany 69, 17003, Girona, Catalonia, Spain
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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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Ghosh S, Changotra A, Petrone DA, Isomura M, Carreira EM, Sunoj RB. Role of Noncovalent Interactions in Inducing High Enantioselectivity in an Alcohol Reductive Deoxygenation Reaction Involving a Planar Carbocationic Intermediate. J Am Chem Soc 2023; 145:2884-2900. [PMID: 36695526 DOI: 10.1021/jacs.2c10975] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The involvement of planar carbocation intermediates is generally considered undesirable in asymmetric catalysis due to the difficulty in gaining facial control and their intrinsic stability issues. Recently, suitably designed chiral catalyst(s) have enabled a guided approach of nucleophiles to one of the prochiral faces of carbocations affording high enantiocontrol. Herein, we present the vital mechanistic insights from our comprehensive density functional theory (B3LYP-D3) study on a chiral Ir-phosphoramidite-catalyzed asymmetric reductive deoxygenation of racemic tertiary α-substituted allenylic alcohols. The catalytic transformation relies on the synergistic action of a phosphoramidite-modified Ir catalyst and Bi(OTf)3, first leading to the formation of an Ir-π-allenyl carbocation intermediate through a turn-over-determining SN1 ionization, followed by a face-selective hydride transfer from a Hantzsch ester analogue to yield an enantioenriched product. Bi(OTf)3 was found to promote a significant number of ionic interactions as well as noncovalent interactions (NCIs) with the catalyst and the substrates (allenylic alcohol and Hantzsch ester), thus providing access to a lower energy route as compared to the pathways devoid of Bi(OTf)3. In the nucleophilic addition, the chiral induction was found to depend on the number and efficacy of such key NCIs. The curious case of reversal of enantioselectivity, when the α-substituent of the allenyl alcohol is changed from methyl to cyclopropyl, was identified to originate from a change in mechanism from an enantioconvergent pathway (α-methyl) to a dynamic kinetic asymmetric transformation (α-cyclopropyl). These molecular insights could lead to newer strategies to tame tertiary carbocations in enantioselective reactions using suitable combinations of catalysts and additives.
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Affiliation(s)
- Supratim Ghosh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Avtar Changotra
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - David A Petrone
- Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, ETH Zürich, 8093 Zürich, Switzerland.,Department of Process Research & Development, Merck & Co., Inc., MRL, Rahway, New Jersey 07065, United States
| | - Mayuko Isomura
- Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Erick M Carreira
- Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Raghavan B Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Teixeira P, Bastin S, César V. Fused Polycyclic NHC Ligands in Gold Catalysis: Recent Advances. Isr J Chem 2022. [DOI: 10.1002/ijch.202200051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Paul Teixeira
- LCC-CNRS Université de Toulouse, CNRS 205 route de Narbonne F-31077 Toulouse France
| | - Stéphanie Bastin
- LCC-CNRS Université de Toulouse, CNRS 205 route de Narbonne F-31077 Toulouse France
| | - Vincent César
- LCC-CNRS Université de Toulouse, CNRS 205 route de Narbonne F-31077 Toulouse France
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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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