A highly selective and sensitive rhodamine B-based chemosensor for Sn⁴⁺ in water-bearing and biomaging and biosensing...

A novel colorimetric-fluorescent dual-mode chemosensor (JT5) based on rhodamine B has been produced for monitoring Sn⁴⁺ in the DMSO/H₂O (4:1, v/v) medium. It has high sensitivity, a low detection limit, a short response time (1 s) and high stability, and can still be maintained after two weeks with the red dual fluorescence/ colorimetric response. Enhancement of red fluorescence (591 nm) and red colorimetric (567 nm) response of JT5 by Sn⁴⁺ addition. The electrostatic potential of the sensor JT5 molecule was simulated to speculate on the sensing mechanism, and the IR, mass spectrometry and ¹H NMR titration were utilized to further demonstrate that JT5 was coordinated to Sn⁴⁺ with a 1:1 type, the rhodamine spironolactam ring of JT5 opens up to form a penta-membered ring with Sn⁴⁺, meanwhile, its system may have chelation enhanced fluorescence (CHEF) effect. In addition, theoretical calculations were carried out to give the energy gaps of JT5 and [JT5 + Sn⁴⁺] as well as to simulate the electronic properties of the maximal absorption peaks. Notably, the sensor JT5 was successfully applied to monitoring Sn⁴⁺ in zebrafish, and the JT5-loaded filter paper provided a solid-state platform for detecting Sn⁴⁺ by both naked eye and fluorescent methods. In summary, this work contributes to monitoring Sn⁴⁺ in organisms and solid-state materials and promotes understanding of Sn⁴⁺ functions in biological systems, environments, and solid-state materials.