UCL logo

UCL Discovery

UCL home » Library Services » Electronic resources » UCL Discovery

Towards a Molecular Understanding of Cation-Anion Interactions-Probing the Electronic Structure of Imidazolium Ionic Liquids by NMR Spectroscopy, X-ray Photoelectron Spectroscopy and Theoretical Calculations

Cremer, T; Kolbeck, C; Lovelock, KRJ; Paape, N; Wolfel, R; Schulz, PS; ... Steinruck, HP; + view all (2010) Towards a Molecular Understanding of Cation-Anion Interactions-Probing the Electronic Structure of Imidazolium Ionic Liquids by NMR Spectroscopy, X-ray Photoelectron Spectroscopy and Theoretical Calculations. CHEM-EUR J , 16 (30) 9018 - 9033. 10.1002/chem.201001032.

Full text not available from this repository.

Abstract

Ten [C(8)C(1)Im](+) (1-methyl-3-octylimidazolium)-based ionic liquids with anions Cl-, Br-, I-, [NO3](-), [BE4](-), [TfO](-), [PF6](-), [Tf2N](-), [Pf(2)N](-), and [FAP](-) (TfO=trifluoromethylsulfonate, Tf2N=bis(trifluoromethylsulfonyl)imide, Pf(2)N=bis(pentafluoroethylsulfonyl)imide, FAP=tris-(pentafluoroethyl)trifluorophosphate) and two [C(8)C(1)C(1)Im](+) (1,2-dimethyl-3-octylimidazolium)-based ionic liquids with anions Br- and [Tf2N](-) were investigated by using X-ray photoelectron spectroscopy (XPS), NMR spectroscopy and theoretical calculations. While H-1 NMR spectroscopy is found to probe very specifically the strongest hydrogen-bond interaction between the hydrogen attached to the C-2 position and the anion, a comparative X.PS study provides first direct experimental evidence for cation-anion charge-transfer phenomena in ionic liquids as a function of the ionic liquid's anion. These charge-transfer effects are found to be surprisingly similar for [C(8)C(1)Im](+) and [C(8)C(1)C(1)Im](+) salts of the same anion, which in combination with theoretical calculations leads to the conclusion that hydrogen bonding and charge transfer occur independently from each other, but are both more pronounced for small and more strongly coordinating anions, and are greatly reduced in the case of large and weakly coordinating anions.

Type:Article
Title:Towards a Molecular Understanding of Cation-Anion Interactions-Probing the Electronic Structure of Imidazolium Ionic Liquids by NMR Spectroscopy, X-ray Photoelectron Spectroscopy and Theoretical Calculations
DOI:10.1002/chem.201001032
Keywords:charge transfer, density functional calculations, electronic interactions, ionic liquids, NMR spectroscopy, X-ray photoelectron spectroscopy, PHYSICOCHEMICAL PROPERTIES, SURFACE-COMPOSITION, MAGNETIC-RESONANCE, CHEMICAL-SHIFTS, FORCE-FIELD, IN-VACUO, TEMPERATURE, DYNAMICS, DENSITY, XPS
UCL classification:UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Chemistry

Archive Staff Only: edit this record