A Ag+-selective “off–on” probe based on a naphthalimide derivative

A new naphthalimide-based derivative L bearing an S-benzyldithiocarbazate moiety was synthesized as an “off–on” probe for Ag+. The new probe has high binding selectivity for Ag+ in water media with a detection limit of Ag+ down to 270 nM. Based on the Ag+-induced inhibition of a PET process and restriction of CN rotation, the coordination mode of 1 : 1 between L and Ag+ was proposed.