Fluorescence chemosensing and bioimaging of metal ions using schiff base probes working through photo-induced electron transfer (PET)

Though metal ions like copper, iron, zinc, etc. are essential, but their dyshomeostasis is associated with several disorders. Therefore, fast, sensitive, and cost-effective monitoring of these cations will have a significant impact. Many recently reported small organic molecules were able to detect a specific metal ion because of certain variations in the electron/charge transfer processes occurring in those molecules after binding with metal ions. In this context, Schiff base molecules were widely used as fluorescence turn-on/turn-off probes for the detection of metal ions like Al3+, Cu2+, Zn2+, Fe3+, Ag+, heavy metal ions, etc. In this article, we have reviewed the recent developments in fluorimetric chemosensing of metal ions by Schiff bases based on the photo-induced electron transfer (PET) process. A variety of examples have been discussed in which PET was used as a cation recognition mechanism. Particular focus is placed on the molecular probes used for sensing, including their design, selectivity, sensitivity, and in some cases their potential bioimaging applications.