| Autor: |
Weiß N; Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany. stefan.spange@chemie.tu-chemnitz.de., Schmidt CH; Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany. stefan.spange@chemie.tu-chemnitz.de., Thielemann G; Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany. stefan.spange@chemie.tu-chemnitz.de., Heid E; University of Vienna, Faculty of Chemistry, Institute for Computational Biological Chemistry, Währingerstr. 17, A-1090 Vienna, Austria. christian.schroeder@univie.ac.at., Schröder C; University of Vienna, Faculty of Chemistry, Institute for Computational Biological Chemistry, Währingerstr. 17, A-1090 Vienna, Austria. christian.schroeder@univie.ac.at., Spange S; Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany. stefan.spange@chemie.tu-chemnitz.de. |
| Abstrakt: |
The Kamlet-Taft dipolarity/polarizability parameters π* for various ionic liquids were determined using 4-tert-butyl-2-((dicyanomethylene)-5-[4-N,N-diethylamino)-benzylidene]-Δ3-thiazoline and 5-(N,N-dimethylamino)-5'-nitro-2,2'-bithiophene as solvatochromic probes. In contrast to the established π*-probe N,N-diethylnitroaniline, the chromophores presented here show excellent agreement with polarity measurement using the chemical shift of 129Xe. They do not suffer from additional bathochromic UV/vis shifts caused by hydrogen-bonding resulting in too high π*-values for some ionic liquids. In combination with large sets of various ionic liquids, these new chromophores thereby allow for detailed analysis of the physical significance of π* and the comparison to quantum-mechanical methods. We find that π* correlates strongly with the ratio of molar refractivity to molar volume, and thus with the refractive index. |
