Skip to content
Accessible Unlicensed Requires Authentication Published by Oldenbourg Wissenschaftsverlag February 7, 2014

Investigation of Molecular Solvents and Ionic Liquids with a Dual Probe

Veronika Strehmel, Stefan Berdzinski, Peter Strauch, Kerstin Hoffmann-Jacobsen and Bernd Strehmel

Abstract

A dual probe was investigated by UV-Vis, fluorescence, and ESR spectroscopy. It comprises the pyrene chromophore and the paramagnetic 2,2,6,6-tetramethylpiperidinyl-N-oxyl radical that are covalently linked together via an ester bridge. The dual probe was used to investigate molecular solvents of different polarity as well as ionic liquids bearing either imidazolium or pyrrolidinium cations and various anions, such as bis(trifluoromethylsulfonyl)imide, tetrafluoroborate, tris(pentafluoroethyl)trifluorophosphate, or dicyanamide. The dual probe does not show solvatochromism that is typical for some pyrenes. Furthermore, the dual probe is considerable less mobile compared to 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) without additional substituent as detected by ESR spectroscopy. This is caused by the bulky pyrenyl substituent bound at the dual probe resulting in a reduced mobility of the dual probe.

Received: 2013-9-27
Accepted: 2014-1-1
Published Online: 2014-2-7
Published in Print: 2014-3-28

©2014 Walter de Gruyter Berlin/Boston