Highly modulated supported triazolium-based ionic liquids: direct control of the electronic environment on Cu nanoparticles CNAP | Universidad Mayor

12 February 2020

Highly modulated supported triazolium-based ionic liquids: direct control of the electronic environment on Cu nanoparticles

Pamela Sepulveda

C. Valdevenito, J. Pinto, M. Nazarkovsky, G. Chacon, O. Martínez-Ferraté, K. Wrighton- Araneda, D. Cortés-Arriagada, M.B. Camarada, J. Alves Fernandes, G. Abarca* (2020). Highly modulated supported triazolium-based ionic liquids: direct control of the electronic environment on Cu nanoparticles. Nanoscale Advances.

Abstract: A series of new triazolium-based supported ionic liquids (SILPs), decorated with Cu NPs, were successfully prepared and applied to the N-arylation of aryl halides with anilines. The triazoles moieties were functionalised using copper-catalysed azide–alkyne cycloaddition. SILP surface characterisation showed a strong correlation between the triazolium cation volume and textural properties. STEM images showed well-dispersed Cu NPs on SILPs with a mean diameter varying from 3.6 to 4.6 nm depending on the triazolium cation used. Besides, XPS results suggest that the Cu(0)/Cu(I) ratio can be modulated by the electronic density of triazolium substituents. XPS and computational analysis gave mechanistic insights into the Cu NP stabilisation pathways, where the presence of electron-rich groups attached to a triazolium ring plays a critical role in leading to a cation adsorption pathway (Eads = 72 kcal mol−1). In contrast, less electron-rich groups favour the anion adsorption pathway (Eads = 63 kcal mol−1). The Cu@SILP composite with electron-rich groups showed the highest activity for the C–N Ullmann coupling reaction, which suggests that electron-rich groups might act as an electron-like reservoir to facilitate oxidative addition for N-arylation. This strategy firmly suggests the strong dependence of the nature of triazolium-based SILPs on the Cu NP surface active sites, which may provide a new environment to confine and stabilise MNPs for catalytic applications.

10.1039/d0na00055h 
800 8064Lab5 Nanotecnología

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