Theoretical investigation of rhodamine6g derivative as fluorescence metal ion sensor

The structural, energetic and optical properties of a Rhodamine6G derivative as the fluoroionphore for metal ion detection, particularly mercury, have been investigated using the time-dependent density functional theory (TD-DFT), compared to experiments. The TD-DFT calculations with the B3LYP method were conducted in the absence and the presence of metal ions. The results indicate that the absorption peaks of the pristine molecules are located at 236 and 282 nm, whereas the selective Hg²⁺ binding peaks emerge at 263, 371 and 551 nm. A distinctive new band emerges around 550 nm, in accordance with the experiments, attributed to the metal-to-ionophore electron transfer. © 2014 Taylor & Francis Group, LLC.