A review: Red/near‐infrared (NIR) fluorescent probes based on nucleophilic reactions of H2S since 2015

Abstract The topics of human health and disease are always the focus of much attention. Hydrogen sulfide (H 2 S), as a double‐edged sword, plays an important role in biological systems. Studies have revealed that endogenous H 2 S is important to maintain normal physiological functions. Conversely, abnormal levels of H 2 S may contribute to various diseases. Due to the importance of H 2 S in physiology and pathology, research into the effects of H 2 S has been active in recent years. Fluorescent probes with red/near‐infrared (NIR) emissions (620–900 nm) are more suitable for imaging applications in vivo , because of their negligible photodamage, deep tissue penetration, and maximum lack of interference from background autofluorescence. H 2 S, an ‘evil and positive’ molecule, is not only toxic, but also produces significant effects; a ‘greedy’ molecule, is not only a strong nucleophile under physiological conditions, but also undergoes a continuous double nucleophilic reaction. Therefore, in this tutorial review, we will highlight recent advances made since 2015 in the development and application of red/NIR fluorescent probes based on nucleophilic reactions of H 2 S.