Slavik, Petr orcid.org/0000-0002-3326-6169 and Smith, David Kelham orcid.org/0000-0002-9881-2714 (2020) Hybrid Hydrogels Loaded with Palladium Nanoparticles – Catalysts for Environmentally-Friendly Sonogashira and Heck Cross-Coupling Reactions. Tetrahedron. 131344. ISSN 0040-4020
Abstract
Palladium nanoparticles (PdNPs) were encapsulated within hybrid hydrogels made from an acylhydrazide-functionalised 1,3:2,4-dibenzylidene sorbitol (DBS-CONHNH2) low-molecular-weight gelator (LMWG) combined with agarose polymer gelator via in situ reduction of Pd(II). These heterogeneous gel-phase catalysts were successfully applied for copper-, amine- and phosphine-free Sonogashira cross-coupling reactions under environmentally-friendly conditions without the need for inert atmosphere reaction conditions. The PdNP-loaded gel was reused in Sonogashira couplings up to at least five times with no adverse effect on yield. The performance of solvated PdNP-loaded gel catalysts was compared with the dried xerogels. The xerogels can be used at higher temperatures, enhancing reaction kinetics albeit lowering reaction selectivity, but unlike the solvated gels, were unable to be easily recycled and reused. The PdNP-loaded gels also had good activity in Heck reactions, and although longer reaction times or higher temperatures were required than for the Sonogashira reaction, the reaction conditions were mild for a Heck coupling. In summary, we demonstrate a ‘waste-to-wealth’ methodology in which Pd(II) ‘waste’ is converted into a valuable gel-phase catalyst that can be used for green Sonogashira and Heck cross-coupling reactions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 Elsevier Ltd. All rights reserved. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) |
Depositing User: | Pure (York) |
Date Deposited: | 17 Jun 2020 23:08 |
Last Modified: | 15 Mar 2025 00:09 |
Published Version: | https://doi.org/10.1016/j.tet.2020.131344 |
Status: | Published online |
Refereed: | Yes |
Identification Number: | 10.1016/j.tet.2020.131344 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:161962 |
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Description: Hybrid Hydrogels Loaded with Palladium Nanoparticles – Catalysts for Environmentally-Friendly Sonogashira and Heck Cross-Coupling Reactions
Licence: CC-BY-NC-ND 2.5