1H, 19F-HOESY and PGSE diffusion studies on ionic liquids:: The effect of co-solvent on structure

H-1, F-19-HOESY studies on the ionic liquid based on 1-butyl-3-methylimidazolium tetrafluoroborate, [C(4)C(1)im]BF4, [C(4)C(1)im]-[N(OTf)(2)], and, partially, [C(4)C(1)im]PF6, are reported. The addition of methanol separates the ions; however, in dichloromethane solution the anions and cations show strong HOESY contacts even after dilution and taken together with the PGSE diffusion measurements, the data suggest strong ion pairing in this solvent. (c) 2005 Elsevier B.V. All rights reserved.