Influence of chiral ionic liquids on the excited-state properties of naproxen analogs.
The synthesis and decolorization of chiral room-temperature ionic liquids based upon 1-methyl imidazole and chloromethyl menthyl ether is reported. The excellent optical quality of these solvents permits the investigation of the effects of the two enantiomers on the excited-state photophysics of (S)-N-methyl-2-pyrrolidinemethyl 2(S)-(6-methoxy-2-naphthyl)propionate [(S,S)-NPX-PYR]. Whereas in conventional bulk polar solvents such as acetonitrile, (S,S)-NPX-PYR is known to execute excited-state intramolecular electron transfer and to form exciplexes, in these chiral solvents these nonradiative processes are absent. The chiral solvents do, however, induce a small but reproducible (approximately 10%) stereodifferentiation in the fluorescence lifetime of (S,S)-NPX-PYR as well as in the parent compound, (S)-naproxen. To our knowledge, this is the first example of chiral ionic liquids inducing such an effect on photophysical properties.
Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
Ramkrishna
R
Adhikary
Sayantan
S
Bose
Prasun
P
Mukherjee
Aniket
A
Thite
George A
GA
Kraus
Aruna B
AB
Wijeratne
Pritesh S
PS
Sharma
Daniel W
DW
Armstrong
Jacob W
JW
Petrich