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. Two birds with one stone: A molecule has been synthesised with two pyrenyl and two imidazolium moieties, which anchored the catalyst tetrachloropalladate to multi-walled carbon nanotubes with high loading. Such noncovalently modified materials could be used up to five times in the Suzuki-Miyaura reaction (see scheme).

Salvo, A., La Parola, V., Liotta, L., Giacalone, F., Gruttadauria, M. (2016). Highly Loaded Multi-Walled Carbon Nanotubes Non-Covalently Modified with a Bis-Imidazolium Salt and their Use as Catalyst Supports. CHEMPLUSCHEM, 81(5), 471-476 [10.1002/cplu.201600023].

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

SALVO, Anna Maria Pia;LA PAROLA, Valeria;LIOTTA, Leonarda Francesca;GIACALONE, Francesco;GRUTTADAURIA, Michelangelo
2016-01-01

Abstract

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. Two birds with one stone: A molecule has been synthesised with two pyrenyl and two imidazolium moieties, which anchored the catalyst tetrachloropalladate to multi-walled carbon nanotubes with high loading. Such noncovalently modified materials could be used up to five times in the Suzuki-Miyaura reaction (see scheme).
2016
Settore CHIM/06 - Chimica Organica
http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%292192-6506/
Salvo, A., La Parola, V., Liotta, L., Giacalone, F., Gruttadauria, M. (2016). Highly Loaded Multi-Walled Carbon Nanotubes Non-Covalently Modified with a Bis-Imidazolium Salt and their Use as Catalyst Supports. CHEMPLUSCHEM, 81(5), 471-476 [10.1002/cplu.201600023].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/178255
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