Two novel rhodamine-perylenediimide fluorescent probes: Synthesis, photophysical properties, and cell imaging

In this study, two novel dual-switch fluorescent chemosensors based on rhodamine-peryleneiimide have been designed and synthesized. The dual-switching behaviors of the sensors were based on the structural transformations of rhodamine and an intramolecular photoinduced electron transfer (PET) process from rhodamine to perylenediimide. These probes exhibited excellent sensitivity to protons with enhanced fluorescence emission from 500 nm to 580 nm. The fluorescence changes of probes were reversible within a wide range of pH values from 2.0 to 11.0. Moreover, the sensors exhibited high selectivity, short response time, and long lifetime toward protons. The possible mechanism was investigated by the DFT calculation and H-1 NMR. According to the experiment of confocal laser scanning microscopy, these probes could be used to detect the acidic pH variations in living cells. (C) 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.