Excited-state proton transfer reaction of a pyrenylurea derivative in the ionic liquid 1-ethyl-3-methylimidazolium acetate

The present study investigated the effects of 1-ethyl-3-methylimidazolium acetate, an ionic liquid, on the excited-state intermolecular proton transfer reaction between 1-pyrene-1-yl-3-[4-(trifluoromethyl)phenyl]urea and ac-etate anion. Moreover, the fluorescence properties and kinetics of the excited-state intermolecular proton transfer reaction were examined in different ratios of dimethylsulfoxide and ionic liquid mixtures. Investigations revealed that the proton transfer reaction rate decreased in excess amount of the ionic liquid. Hence, this finding suggests that the slow reaction of urea compounds was related to the slow reorientation of the 1-ethyl-3-meth-ylimidazolium acetate solvent.