Synthesis And Recognition For Al³⁺,Cu²⁺,H₂S With "Off-On" Fluorescence Based On 7-hydroxytetra-Hydroquinoxaline-6-carbaldehyde Derivatives

In this paper,four types of fluorescence enhanced probes with simple structure were designed and synthesized based on 1,4-diethyl-7-hydroxytetrahydro quinoxaline-6-formaldehyde?DHQC?,and realized recognition for Al³⁺,Cu²⁺and H₂S.The research results about recognition performance of these probes have been obtained and the details were as follows:1.A acylhydrazone derivative?L1?was synthesized and recognized for Al³⁺with good selectivity in DMSO/Tris?7/3,v/v?solution.The fluorescence color of L1change from non-fluorescence to red fluorescence when Al³⁺is added.Probe L1possesses a maximum emission wavelength of 640 nm,which lies on the near-infrared range,a large stokes shift?170 nm?,a detection limit of 5.08×10^-7mol/L.Probe L1 can detect Al³⁺in lake water,river water,and tap water samples and can also be used for fluorescence imaging of Al³⁺in MCF-7 cells.2.A schiff base derivative?L2?based on DHQC was synthesized and recognized specifically for Cu²⁺with well anti-interference and fast responding in a THF/tris?7/3,v/v?solution.The fluorencence color of L2 changes from weak red fluorescence to strong green fluorescence after adding Cu²⁺.Probe L2 possesses a detection limit of 1.19×10^-7 mol/L and can be used to detect Cu²⁺in actual water samples.3.A benzothiazolium derivatives?L3?was synthesized and recognized for H₂S with well selectivity and sensitivity,good anti-interference and detection limit of2.5×10^-66 mol/L in DMSO solution.The solution color of L3 changes from blue to colorless,and fluorescence color of L3 changed from non-fluorescence to strong yellow-green fluorescence after adding H₂S.4.A near-infrared emission fluorescent probe L4 was synthesized by using DHQC and benzothiazole-2-acetonitrile,and recognized for H₂S with well selectivity and sensitivity in THF/PBS?3/7,v/v,pH=7.4?buffer solution.The color of L4 changes from non-fluorescence to red fluorescence after adding H₂S.Probe L4 possesses a maximum emission wavelength of 650 nm,which lie on the near-infrared range,a large stokes shift?124 nm?and a detection limit of 35 nmol/L.In addition,probe L4 is capable of detecting H₂S in actual water samples and living cells.