A simple colorimetric sensor for biologically important anions based on intramolecular charge transfer (ICT)
A sensitive colorimetric sensor (1) based on 4,5-dinitrobenzene-1,2-diamine was designed and synthesized. Binding of anions such as AcO−, F− and H2PO4- results in a notable change in the visible region of spectrum (an approximately 90 nm red shift), which can be detected by the ‘naked-eye’. Furthermore, the binding ability was evaluated by UV–vis titration experiments as following: AcO− > F− > H2PO4- ≫ Cl−, Br−, I−. The nature of the color change of 1 induced by AcO− was due to the intramolecular charge transfer (ICT) which was confirmed by X-ray crystal structure and 1H NMR titration spectra.
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 97, Issue 1, 6 October 2009, Pages 18–21