Dealing with supramolecular structure for ionic liquids: a DOSY NMR approach

Author(s)

Zanatta, Marcileia ^[1] ; Antunes, Victor U. ^[2] ; Tormena, Claudio F. ^[2] ; Dupont, Jairton ^[1] ; dos Santos, Francisco P. ^[1]

Affiliation

^[1] Univ Fed Rio Grande do Sul, Inst Chem, Ave Bento Goncalves 9500, BR-91501970 Porto Alegre, RS - Brazil

^[2] Univ Estadual Campinas, UNICAMP, Inst Chem, POB 6154, BR-13083970 Campinas, SP - Brazil

• Document type: Journal article
• Source: Physical Chemistry Chemical Physics; v. 21, n. 5, p. 2567-2571, FEB 7 2019.
• Web of Science Citations: 5

Abstract

Diffusion-ordered spectroscopy (DOSY) is arguably a powerful method for the NMR analysis of ionic liquids, since the self-diffusion coefficients for cations and anions can be measured straightforwardly. In this work, the dynamic-structural behaviour of imidazolium ionic liquids containing different anions has been investigated by experimental measurements of direct H-1 diffusion coefficients in chloroform and water solutions. The influence of ion structure has been tested by using six IL salts formed by the association of different cations (1-n-butyl-3-methylimidazolium, 1,2,3-trimethylimidazolium and tetra-n-butylammonium) with different anion structures (prolinate, acetate and o-trifluoromehtylobenzoate). The influence of IL concentration (from 0.01 to 0.5 mol L-1) was also evaluated for BMI<bold>Pro</bold>. The contact ion pairs (or aggregates) are maintained in both chloroform and water within the range of concentrations investigated. In the particular case of 1,2,3-trimethylimidazolium imidazolate (TMI<bold>Im</bold>) containing confined water in DMSO the maintenance of the contact ion pairs depends on the water content which may even disrupt the IL supramolecular structure. (AU)

• FAPESP's process: 15/08541-6 - Nuclear magnetic resonance spectroscopy: beyond molecular structure assignment
• Grantee: Claudio Francisco Tormena
• Support Opportunities: Research Projects - Thematic Grants