Study on a Novel Colorimetric and Off-On Fluorescent Chemosensor with Aggregation-Induced Emission Effect for Detection of Fe3+ in Aqueous Solution

A novel tetraphenylethyene-functionalized rhodamine derivative (TPE-RhB) was designed and synthesized. FT-IR, NMR, MS, elemental analysis, cyclic voltammetry electrochemical analysis, UV-Vis, and molecular fluorescence were used to study its structure, electrochemical and optical properties. These results showed that the electron affinity of TPE-RhB was 3.66 eV, which is expected to develop electron-transporting material. A significant aggregation-induced emission (AIE) effect of TPE-RhB was found through solution fluorescence test in different V(EtOH): V(H2O) mixed solvents. Furthermore, sensor TPE-RhB displayed highly seletive and sensitive off-on fluorescence response and naked-eye color change to Fe3+ in EtOH/H2O (V:V= 1:1, Tris-HCl pH 7.0) solution. The association constant between TPE-RhB and Fe3+ was detected to be 3.12x10(3) and the detection limit was calculated to be 3.53x10(-7) mol.L-1. The probe TPE-RhB also showed a good linearity (R-2= 0.9915) in the range of 60 similar to 180 mu mol/L of Fe3+ ion. The mechanisms had been supported by Job's plot evalution, fluorescence titrations, and H-1 NMR spectroscopic studies.