Instantaneous fluorescent probe for the specific detection of H2S

Fluorescent probes based on nucleophilic aromatic substitution reactions for reactive sulfur and selenium species: Recent progress, applications, and design strategies

“…Due to the inherently low degree of dissociation of a phenyl-O ether group, although a phenyl-O linkage moiety bearing a single substituent can respond to RSS and RSeS, the response times are too long and the selectivity is poor [161] . More popular phenyl-O ether groups are those bearing two substituents, which show shorter response times to RSS and RSeS and improved selectivity, most notably the 2,4-dinitrophenyl-O ether group [162] , [163] , [164] , [165] , [166] . The phenyl-O ether group itself can respond to RSS and RSeS, but it does not have a quenching effect, so it is not very suitable for detection [161] .…”

“…Response times of phenyl-O ether groups to the detection group of RSS and RSeS are longer, the selectivity is not high, but the fluorescence is strong [161] . However, introducing electron-withdrawing groups at other positions on the benzene ring of the detection group can shorten response times and quench the fluorescence of the fluorophore [162] , [163] , [164] , [165] , [166] . Therefore, for RSS and RSeS with low p K a values, nitrophenyl-O ethers are good choices [167] , [168] , [169] , [170] .…”

Emerging analytical tools for the detection of the third gasotransmitter H2S, a comprehensive review

“…: very fast response time (4 sec. ), NIR emission (680 nm), 115 fold fluorescence enhancement, linearity range (1–10 µM), good sensitivity (LOD = 11 nM), satisfactory Stokes shift (90 nm λ ex/em = 590/680 nm), aqueous detection medium (PBS), low cytotoxicity against different cellular lines Application: lysosome-targeting/cell (HeLa) and mice (monitoring localized diffusion after intraperitoneal injection) [59] F12 Adv. : relative rapid response time (10 min), NIR emission (663 nm), very large Stokes shift (244 nm), 105-fold fluorescence enhancement, good sensitivity (LOD = 42 nM), good selectivity, linear range 0 – 50 µM, wide pH range (6 – 10), good quantum yield = 0.22 Disadv.…”

“…This results in one or two fluorescent compounds 2,4-dinitrophenyl-based probes: The 2,4-dinitrophenyl moiety acts as a quencher of the fluorophore moiety via photo-induced electron transfer (PET). 2,4-Dinitrophenyl moiety can be linked to the fluorophore nucleus such as cyanine [59] , xanthene [60] , pyridinium derivative [46] , pyrimidine derivative [61] , functionalized graphene quantum dots [62] via an ether linkage, or a sulfonamide linkage to fluorophore as dicyanoisophorone [63] , curcumin [64] , coumarin [65] . …”

“…A sensitive fluorescent sensor, F23 (LOD = 11 nM) contains an ether-linkage and cyanine derivative (fluorophore) was developed to react instantaneously with H 2 S (4 sec) exhibiting 115-fold fluorescence enhancement (Turn-on). It offers a water-soluble sensor that has been used in cellular imaging (HeLa and HepG2), lysosomes, and in vivo in mice [59] . The fluorescence enhancement is generally reflecting the increase in the fluorescence intensity in the presence of sulfide compared to that of the probe alone under the give reaction conditions (Time, temperature, pH, ….…).…”