λ−carrageenan based ammonium-tagged Hoveyda-Grubbs type catalyst: Novel heterogeneous system for olefin metathesis

• Published in: Journal of organometallic chemistry 2024-08, Vol.1016, p.123255, Article 123255
• Main Authors: Levy-Ontman, Oshrat, Gliksberg, Natalia, Tzur, Eyal, Wolfson, Adi
• Format: Article
• Language: English
• Subjects: Carrageenan; Catalysis; Immobilization; Olefin metathesis; Polysaccharides
• ISSN: 0022-328X
• DOI: 10.1016/j.jorganchem.2024.123255

•An ammonium tagged Hoveyda-Grubbs complex FixCat was heterogenized in λ-carrageenan.•The activity of λ-FixCat in ring-closing metathesis using olefins was superior in toluene.•The new heterogeneous catalyst was successfully recycled five times.•λ-carrageenan matrix structure was altered by the addition of λ-FixCat. An ammonium tagged Hoveyda-Grubbs-type catalyst, i.e., FixCat, was non-covalently heterogenized for the first time in a λ−carrageenan xerogel via ion-exchange, which was confirmed by FTIR, SEM-EDS and TGA analyses. The new heterogeneous catalyst, i.e., λ−FixCat, was successfully employed in ring-closing metathesis using representative olefins in several solvents without leaching of the complex. The best catalytic performances were detected in the nonpolar solvents hexane and toluene. The activity of λ−FixCat was shown to be superior in toluene in terms of catalyst reusability, as it was easily separated from the reaction mixture, and it was successfully recycled five times. This study is part of our ongoing efforts to demonstrate the applicability of natural polysaccharides as supports for various catalysts. [Display omitted]