Articles producció científica> Química Física i Inorgànica

Triazolylidene Iridium Complexes for Highly Efficient and Versatile Transfer Hydrogenation of C=O, C=N, and C=C Bonds and for Acceptorless Alcohol Oxidation

  • Identification data

    Identifier: imarina:4123814
    Authors:
    Mazloomi ZPretorius RPàmies OAlbrecht MDiéguez M
    Abstract:
    © 2017 American Chemical Society. A set of iridium(I) and iridium(III) complexes is reported with triazolylidene ligands that contain pendant benzoxazole, thiazole, and methyl ether groups as potentially chelating donor sites. The bonding mode of these groups was identified by NMR spectroscopy and X-ray structure analysis. The complexes were evaluated as catalyst precursors in transfer hydrogenation and in acceptorless alcohol oxidation. High-valent iridium(III) complexes were identified as the most active precursors for the oxidative alcohol dehydrogenation, while a low-valent iridium(I) complex with a methyl ether functionality was most active in reductive transfer hydrogenation. This catalyst precursor is highly versatile and efficiently hydrogenates ketones, aldehydes, imines, allylic alcohols, and most notably also unpolarized olefins, a notoriously difficult substrate for transfer hydrogenation. Turnover frequencies up to 260 h-1were recorded for olefin hydrogenation, whereas hydrogen transfer to ketones and aldehydes reached maximum turnover frequencies greater than 2000 h-1. Mechanistic investigations using a combination of isotope labeling experiments, kinetic isotope effect measurements, and Hammett parameter correlations indicate that the turnover-limiting step is hydride transfer from the metal to the substrate in transfer hydrogenation, while in alcohol dehydrogenation, the limiting step is substrate coordination to the metal center.
  • Others:

    Author, as appears in the article.: Mazloomi Z; Pretorius R; Pàmies O; Albrecht M; Diéguez M
    Department: Química Física i Inorgànica Química Física i Inorgànica
    URV's Author/s: Diéguez Fernández, Montserrat / Pamies Ollé, Oscar
    Keywords: Clean water and sanitation
    Abstract: © 2017 American Chemical Society. A set of iridium(I) and iridium(III) complexes is reported with triazolylidene ligands that contain pendant benzoxazole, thiazole, and methyl ether groups as potentially chelating donor sites. The bonding mode of these groups was identified by NMR spectroscopy and X-ray structure analysis. The complexes were evaluated as catalyst precursors in transfer hydrogenation and in acceptorless alcohol oxidation. High-valent iridium(III) complexes were identified as the most active precursors for the oxidative alcohol dehydrogenation, while a low-valent iridium(I) complex with a methyl ether functionality was most active in reductive transfer hydrogenation. This catalyst precursor is highly versatile and efficiently hydrogenates ketones, aldehydes, imines, allylic alcohols, and most notably also unpolarized olefins, a notoriously difficult substrate for transfer hydrogenation. Turnover frequencies up to 260 h-1were recorded for olefin hydrogenation, whereas hydrogen transfer to ketones and aldehydes reached maximum turnover frequencies greater than 2000 h-1. Mechanistic investigations using a combination of isotope labeling experiments, kinetic isotope effect measurements, and Hammett parameter correlations indicate that the turnover-limiting step is hydride transfer from the metal to the substrate in transfer hydrogenation, while in alcohol dehydrogenation, the limiting step is substrate coordination to the metal center.
    Thematic Areas: Química Physical and theoretical chemistry Medicina i Materiais Interdisciplinar Inorganic chemistry General medicine Farmacia Engenharias iii Engenharias ii Engenharias i Ciências biológicas iii Ciências biológicas ii Ciências biológicas i Ciências agrárias i Chemistry, inorganic & nuclear Chemistry (miscellaneous) Biotecnología Astronomia / física
    licence for use: https://creativecommons.org/licenses/by/3.0/es/
    ISSN: 00201669
    Author's mail: oscar.pamies@urv.cat montserrat.dieguez@urv.cat
    Author identifier: 0000-0002-2352-8508 0000-0002-8450-0656
    Last page: 11298
    Record's date: 2024-11-16
    Journal volume: 56
    Papper version: info:eu-repo/semantics/submittedVersion
    Link to the original source: https://pubs.acs.org/doi/10.1021/acs.inorgchem.7b01707
    Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
    Papper original source: Inorganic Chemistry. 56 (18): 11282-11298
    APA: Mazloomi Z; Pretorius R; Pàmies O; Albrecht M; Diéguez M (2017). Triazolylidene Iridium Complexes for Highly Efficient and Versatile Transfer Hydrogenation of C=O, C=N, and C=C Bonds and for Acceptorless Alcohol Oxidation. Inorganic Chemistry, 56(18), 11282-11298. DOI: 10.1021/acs.inorgchem.7b01707
    Article's DOI: 10.1021/acs.inorgchem.7b01707
    Entity: Universitat Rovira i Virgili
    Journal publication year: 2017
    First page: 11282
    Publication Type: Journal Publications
  • Keywords:

    Chemistry (Miscellaneous),Chemistry, Inorganic & Nuclear,Inorganic Chemistry,Physical and Theoretical Chemistry
    Clean water and sanitation
    Química
    Physical and theoretical chemistry
    Medicina i
    Materiais
    Interdisciplinar
    Inorganic chemistry
    General medicine
    Farmacia
    Engenharias iii
    Engenharias ii
    Engenharias i
    Ciências biológicas iii
    Ciências biológicas ii
    Ciências biológicas i
    Ciências agrárias i
    Chemistry, inorganic & nuclear
    Chemistry (miscellaneous)
    Biotecnología
    Astronomia / física
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