Highly Loaded Multi-Walled Carbon Nanotubes Non-Covalently Modified with a Bis-Imidazolium Salt and their Use as Catalyst Supports

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• 作者：Dr. Anna Maria Pia Salvo ; Dr. Valeria La Parola ; Dr. Leonarda F. Liotta ; Dr. Francesco Giacalone and Prof. Michelangelo Gruttadauria
• 刊名：ChemPlusChem
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：81
• 期：5
• 页码：471-476
• 全文大小：1353K
• ISSN：2192-6506

文摘

The surfaces of multi-walled carbon nanotubes (MWCNTs) were non-covalently modified using two bis-imidazolium dibromide derivatives having phenyl or pyrene groups. Due to the presence of the two pyrene groups the bis(pyren-1-ylmethylimidazolium) dibromide derivative was immobilised at a loading of about 15–16 wt %, whereas only <3 wt % of the phenyl derivative was immobilised. The presence of the two imidazolium cations helped the immobilisation of tetrachloropalladate ions after exchange with bromide ions. Tetrachloropalladate was used as pre-catalyst in several Suzuki–Miyaura carbon–carbon cross-coupling reactions in water or water/ethanol at 50 °C in only 0.1 mol % and compared with the non-supported pre-catalyst. The MWCNT-supported material was used in five consecutive cycles of the Suzuki–Miyaura reaction. Recycling using phenylboronic acid and 4-bromobenzaldehyde in water/ethanol was achieved with only a minor loss in activity. HRTEM images clearly showed the presence of the bis(pyren-1-ylmethylimidazolium) derivative on the sidewalls of MWCNTs.