Synthesis of Benzothiazole Fluorescent Probe for Detection of N₂H₄·H₂O and HS

O 3 - †

WANG Jinjin,QI Shaolong,DU Jianshi,YANG Qingbiao,SONG Yan,LI Yaoxian

Chem. J. Chinese Universities 2019, 40 (7): 1397-1404. DOI: 10.7503/cjcu20190159

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Based on benzothiazole as fluorophore, ethyl cyanoacetate as recognition group, a new fluorescent probe 3-(2-hydroxy-benzothiazole)-2-cyano-ethyl acrylate(HBT-CN) with dual detection ability for hydrazine hydrate and bisulfite was designed and synthesized. In DMSO/PBS(1：4, volume ratio) buffered condition, the probe displayed good selectivity towards hydrazine and bisulfite with approximate 5.6 times(500 nm) and 7.5 times(458 nm) fluorescence enhancement at 500 and 458 nm, respectively. ¹H NMR, ¹³C NMR and HRMS results showed that during the detection process, HBT-CN undergoed a reduction-condensation reaction with N₂H₄·H₂O, which form a aldehyde hydrazone and emited pale yellow fluorescent signal at 500 nm. And HBT-CN under went a nucleophilic addition reaction with bisulfite and emited blue fluorescent signal at 458 nm. So, differential qualitative and quantitative detection of N₂H₄·H₂O and HS $O 3 -$ can be achieved.

Fig.2 Time-dependent fluorescence intensity changes of HBT-CN(5×10^-6 mol/L) in the presence of N₂H₄·H₂O(1×10^-3 mol/L, λ_ex=399 nm, λ_em=500 nm, slits: 2.5 nm/5 nm)(A) and HS

O 3 -

(1×10^-3 mol/L, λ_ex=399 nm, λ_em=458 nm, slits: 2.5 nm/5 nm)(B)