A multifunctional Schiff base as a fluorescence sensor for Fe 3+ and Zn 2+ ions, and a colorimetric sensor for Cu 2+ and applications.

Chemosensors play important parts in the selective recognition of ions, which is widely applied in various fields of environment, industry and biological sciences. In this work, a chemosensor for multi-metal ions based on rhodamine B derivative was synthesized, which could selectively recognize various metal ions in different solvent system. The addition of Cu2+ caused the color change from colorless to pink in EtOH/H2 O (v/v=1:1) solvent system, which could be quickly identified by the naked eyes with a detection limit of 8.27×10-8 M. In ethanol solution system, the addition of Fe3+ and Zn2+ caused different fluorescence changes with the detection limit of 2.12×10-7 M and 6.64×10-7 M respectively. The binding ratios are 1:1 (1-Cu2+ ), 2:1 (1-Fe3+ ) and 1:1 (1-Zn2+ ), respectively. Meanwhile, the probe 1 was used to detect the trace metal ions in real water samples. Besides, the probe 1 showed sensitive fluorescence signals for Fe3+ in biological cells. The experimental results further verify the application value of the sensor.