Fig. 2: Changes in UV-visible absorption spectra.

Absorbance spectra of a p-2Urea and b m-2Urea in the absence and presence of different amounts of tetrabutylammonium acetate (TBAAc) (orange = 0 eq; grey = 5 eq; light blue = 10 eq; yellowish green = 50 eq; green = 100 eq; purple = 250 eq; red = 500 eq; grey dashed = 4000 eq; brown dashed = 6000 eq; reddish brown dashed = 10,000 eq; light blue dashed = 14000 eq).