Naphthalimide-Rhodamine based chemosensors for colorimetric and fluorescent sensing Hg2+ through different signaling mechanisms in corresponding solvent systems

- Two naphthalimide-Rhodamine derivatives are synthesized for selective sensing Hg2+.
- In CH3CN, R6G-NA exhibits a FRET behavior to Hg2+.
- In CH3CN, spirolactam of RB-NA can be opened by Hg2+ with a block of PET process.
- In CH3CN aqueous solution, Hg2+ can only trigger a PET-OFF progress of RB-NA.
- R6G-NA and RB-NA can exhibit both colorimetric and fluorescent response to Hg2+.
- Both of R6G-NA and RB-NA can reversibly detect Hg2+ within a short response time.