Valdebenito C, Pinto J, Nazarkovsky M, Chacón G, Martínez-Ferraté O, Wrighton-Araneda K, Cortés-Arriagada D, Camarada MB, Alves Fernandes J, Abarca G. Highly modulated supported triazolium-based ionic liquids: direct control of the electronic environment on Cu nanoparticles.
NANOSCALE ADVANCES 2020;
2:1325-1332. [PMID:
36133065 PMCID:
PMC9418861 DOI:
10.1039/d0na00055h]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 05/12/2020] [Accepted: 02/09/2020] [Indexed: 05/15/2023]
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 (E ads = 72 kcal mol-1). In contrast, less electron-rich groups favour the anion adsorption pathway (E ads = 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.
Collapse