Molecular engineering of benzenesulfonyl analogs for visual hydrogen polysulfide fluorescent probes based on Nile red skeleton.

[Display omitted] • A series of probes NR-BS for H 2 S n were synthesized based on Nile red skeleton. • NR-BS4 can detect H 2 S n with high selective, wide linear range and broad pH tolerance. • The detection mechanisms of NR-BS4 were proved by LC-MS and DFT calculations. • NR-BS4 is a powerful tool for detecting the H 2 S n in living cells and zebrafish. Hydrogen polysulfide (H 2 S n , n > 1) has a valuable function in various aspects of biological regulation. Therefore, it is of great significance to realize the visual monitoring of H 2 S n levels in vivo. Herein, a series of fluorescent probes NR-BS were constructed by changing types and positions of substituents on the benzene ring of benzenesulfonyl. Among them, probe NR-BS4 was optimized due to its wide linear range (0 ∼ 350 μM) and little interference from biothiols. In addition, NR-BS4 has a broad pH tolerance range (pH = 4 ∼ 10) and high sensitivity (0.140 μM). In addition, the PET mechanism of probe NR-BS4 and H 2 S n was demonstrated by DFT calculations and LC-MS. The intracellular imaging studies indicate that NR-BS4 can be successfully devoted to monitor the levels of exogenous and endogenous H 2 S n in vivo. [ABSTRACT FROM AUTHOR]