Selective optical chemosensors of Fe3+ ions using 1H-indole-2,3-dione

1H-Indole-2,3-dione has attracted many attentions in the field of organic synthesis due to its easy modification with other organic compounds. On the other hand, 1H-indole-2,3-dione compound could also be used as chemosensor agent because it contains amide and carbonyl functional groups, which are able for binding as well as chelating metal ions. In the present work, we reported that 1H-indole-2,3-dione compound exhibits high sensing capability as well as high selective detection of Fe3+ ions through enhancement of its absorption peak at ultraviolet region. Particularly, a series of 0.5 mM of metal ions (Na+, K+, Ba2+, Ca2+, Co2+, Cu2+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, Zn2+, Au3+, Al3+, Fe3+ and La3+) in distilled water was simply mixed with 0.05 mM of 1H-indole-2,3-dione in distilled water. Afterward, their UV-Vis spectral changes were recorded by using UV-Vis spectrophotometer. It was found that 1H-indole-2,3-dione itself gave two main absorption peaks at 242 and 302 nm. When the Fe3+ ions were added, the intensity of both absorption peaks was remarkably increased. From the UV-Vis titration experiment, limit of detection value was found to be 17.8 µM while limit of quantitation was found as 59.3 µM. This finding shows that the 1H-indole-2,3-dione gives a promising platform for fluorescent chemosensor agent for sensing of Fe3+ ion.