Perfluoroalkyltricyanoborate and Perfluoroalkylcyanofluoroborate Anions: Building Blocks for Low-Viscosity Ionic Liquids.
Chemistry
; 24(3): 608-623, 2018 Jan 12.
Article
en En
| MEDLINE
| ID: mdl-28884848
The potassium perfluoroalkyltricyanoborates K[Cn F2 n+1 B(CN)3 ] [n=1 (1 d), 2 (2 d)] and the potassium mono(perfluoroalkyl)cyanofluoroborates K[Cn F2 n+1 BF(CN)2 ] [n=1 (1 c), 2 (2 c)] and [Cn F2 n+1 BF2 (CN)]- [n=1 (1 b), 2 (2 b), 3 (3 b), 4 (4 b)] are accessible with perfect selectivities on multi-gram scales starting from K[Cn F2 n+1 BF3 ] and Me3 SiCN. The K+ salts are starting materials for the preparation of salts with organic cations, for example, [EMIm]+ (EMIm=1-ethyl-3-methylimidazolium). These [EMIm]+ salts are hydrophobic room-temperature ionic liquids (RTILs) that are thermally, chemically and electrochemically very robust, offering electrochemical windows up to 5.8â
V. The RTILs described herein, exhibit very low viscosities with a minimum of 14.0â
mPa s at 20 °C for [EMIm]1 c, low melting points down to -57 °C for [EMIm]2 b and extraordinary high conductivities up to 17.6â
mS cm-1 at 20 °C for [EMIm]1 c. The combination of these properties makes these ILs promising materials for electrochemical devices as exemplified by the application of selected RTILs as component of electrolytes in dye-sensitised solar cells (DSSCs, Grätzel cells). The efficiency of the DSSCs was found to increase with a decreasing viscosity of the neat ionic liquid. In addition to the spectroscopic characterisation, single crystals of the potassium salts of the anions 1 b-d, 2 d, 3 b and 4 c as well as of [nBu4 N]2 c have been studied by X-ray diffraction.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Chemistry
Asunto de la revista:
QUIMICA
Año:
2018
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Alemania