Reversible Near-Infrared Fluorescent Probe for Rapid Sensing Sulfur Dioxide and Formaldehyde: Recognition and Photoactivation Mechanism and Applications in Bioimaging and Encryption Ink.

A novel near-infrared (NIR) fluorescent Probe was successfully developed for the reversible detection of sulfur dioxide derivatives and formaldehyde. The purple solution of Probe faded to colorless in 1.8 s with the addition of HSO. Meanwhile, its fluorescence signal disappeared instantaneously with a 39 nM detection limit. The probe exhibited excellent selectivity toward HSO over other potential interfering agents. Then, its absorption and fluorescence bands were able to effectively recover in response to formaldehyde. Remarkably, this reverse process was able to accelerate 84 times under UV light in 122 s and achieved a recovery rate of 98% by UV light, the photoactivation mechanism was fully determined by HRMS and theoretical calculation. Furthermore, we demonstrated that Probe was successfully applied for the detection of sulfur dioxide derivatives and formaldehyde in living cells and data encryption.