ROOM-TEMPERATURE PHOSPHORESCENCE OF INDICANS

The room temperature phosphorescence properties of tryptophan and the indicans indoxyl-β-D-glucoside [3-(β-D-glucosido)indole], 3-indoxylsulphate and 3-indoxylphosphate adsorbed on filter-paper were examined in the presence of the heavy ions caesium and iodide. When caesium was used, the slopes of the log intensity versus log concentration plots increased with the electron-withdrawing ability of the substituent in the 3-position. With iodide, the slopes decreased with the electron-withdrawing ability of that substituent. Fluorescence wavelengths are also presented.