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Kisten P, Manoury E, Lledós A, Whitwood AC, Lynam JM, Slattery JM, Duckett SB, Poli R. Ir I(η 4-diene) precatalyst activation by strong bases: formation of an anionic Ir III tetrahydride. Dalton Trans 2023; 52:2495-2505. [PMID: 36727834 DOI: 10.1039/d2dt04036k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The reaction between [IrCl(COD)]2 and dppe in a 1 : 2 ratio was investigated in detail under three different conditions. [IrCl(COD)(dppe)], 1, is formed at room temperature in the absence of base. In the presence of a strong base at room temperature, hydride complexes that retain the carbocyclic ligand in the coordination sphere are generated. In isopropanol, 1 is converted into [IrH(1,2,5,6-η2:η2-COD)(dppe)] (2) on addition of KOtBu, with k12 = (1.11 ± 0.02) × 10-4 s-1, followed by reversible isomerisation to [IrH(1-κ-4,5,6-η3-C8H12)(dppe)] (3) with k23 = (3.4 ± 0.2) × 10-4 s-1 and k32 = (1.1 ± 0.3) × 10-5 s-1 to yield an equilibrium 5 : 95 mixture of 2 and 3. However, when no hydride source is present in the strong base (KOtBu in benzene or toluene), the COD ligand in 1 is deprotonated, followed by β-H elimination of an IrI-C8H11 intermediate, which leads to complex [IrH(1-κ-4,5,6-η3-C8H10)(dppe)] (4) selectively. This is followed by its reversible isomerisation to 5, which features a different relative orientation of the same ligands (k45 = (3.92 ± 0.11) × 10-4 s-1; k5-4 = (1.39 ± 0.12) × 10-4 s-1 in C6D6), to yield an equilibrated 32 : 68 mixture of 4 and 5. DFT calculations assisted in the full rationalization of the selectivity and mechanism of the reactions, yielding thermodynamic (equilibrium) and kinetic (isomerization barriers) parameters in excellent agreement with the experimental values. Finally, in the presence of KOtBu and isopropanol at 80 °C, 1 is transformed selectively to K[IrH4(dppe)] (6), a salt of an anionic tetrahydride complex of IrIII. This product is also selectively generated from 2, 3, 4 and 5 and H2 at room temperature, but only when a strong base is present. These results provide an insight into the catalytic action of [IrCl(COD)(LL)] complexes in the hydrogenation of polar substrates in the presence of a base.
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Affiliation(s)
- Paven Kisten
- Department of Chemistry, University of York, Heslington, York, YO10 5DD UK. .,CNRS, LCC (Laboratoire de Chimie de Coordination), Université de Toulouse, UPS, INPT, 205 route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France CNRS.
| | - Eric Manoury
- CNRS, LCC (Laboratoire de Chimie de Coordination), Université de Toulouse, UPS, INPT, 205 route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France CNRS.
| | - Agustí Lledós
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Barcelona, Catalonia, Spain
| | - 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.
| | - John M Slattery
- Department of Chemistry, University of York, Heslington, York, YO10 5DD UK.
| | - Simon B Duckett
- Department of Chemistry, University of York, Heslington, York, YO10 5DD UK.
| | - Rinaldo Poli
- CNRS, LCC (Laboratoire de Chimie de Coordination), Université de Toulouse, UPS, INPT, 205 route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France CNRS. .,Institut Universitaire de France, 1, rue Descartes, 75231 Paris Cedex 05, France
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Hermosilla P, García-Orduña P, Lahoz FJ, Polo V, Casado MA. Rh Complexes with Pincer Carbene CNC Lutidine-Based Ligands: Reactivity Studies toward H 2 Addition. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00453] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Pablo Hermosilla
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Pilar García-Orduña
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Fernando J. Lahoz
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Víctor Polo
- Departamento de Química Física and Instituto de Biocomputación y Física de los Sistemas Complejos (BIFI), Universidad de Zaragoza, c/Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Miguel A. Casado
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12, 50009, Zaragoza, Spain
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Hermosilla P, López P, García-Orduña P, Lahoz FJ, Polo V, Casado MA. Amido Complexes of Iridium with a PNP Pincer Ligand: Reactivity toward Alkynes and Hydroamination Catalysis. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00365] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Pablo Hermosilla
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12 50009, Zaragoza, Spain
| | - Pablo López
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12 50009, Zaragoza, Spain
| | - Pilar García-Orduña
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12 50009, Zaragoza, Spain
| | - Fernando J. Lahoz
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12 50009, Zaragoza, Spain
| | - Víctor Polo
- Departamento de Química Física and Instituto de Biocomputación y Física de los Sistemas Complejos (BIFI), Universidad de Zaragoza, c/Pedro Cerbuna 12 50009, Zaragoza, Spain
| | - Miguel A. Casado
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Departamento de Química Inorgánica, CSIC-Universidad de Zaragoza, c/Pedro Cerbuna 12 50009, Zaragoza, Spain
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