Synthesis And Ion Recognition Of Fluorescent Probes Based On Benzothiazole

Benzothiazole derivative is an important class of nitrogen-containing heterocyclic compounds,they have been widely used in the fields of biological and medical sciences.With the development of research,people find that these kinds of compounds have good fluorescence properties.Therefore,in recent years,more and more attention has been devoted to these compounds.We designed and synthesized a series of fluorescent probes based on3-?benzo[d]thiazol-2-yl?-2-hydroxy-5-methylbenzaldehyde structure.The ion recognition properties of the probes were investigated and obtained some meaningful results.The details are as follows.1.A new benzothiazole derived enaminone BTP as fluorescent probe for CN-recognition has been developed.In DMSO/H₂O?95/5,v/v,HEPES 10 mM,pH = 7.4?solution,BTP exhibits high selectivity toward CN-among various anions through colorimetric and fluorescence dual channel changes.With CN-,BTP displays a blue shifted fluorescence enhancement and a color change from orange to yellow green.Moreover,the CN-sensing event possesses excellent anti-interference ability.Sensing mechanism investigations prove that the CN-recognition process undergoes a typical nucleophilic addition of CN-to the enaminone formed BTP.Simple test paper experiments evidenced the practicability of BTP for CN-detection.2.Benzothiazole derived Schiff bases L and L1 as fluorescent probes for different ions recognition have been developed.In ethanol solution,probe L exhibits a highly selective fluorescence response to Zn²⁺ and Mg²⁺ and there is no cross interference between the two metal ions.Inaddition,probe L also has some advantages including high selectivity rapid response.In DMF/H₂O?1/1,v/v?solution,L1 exhibits high selectivity towards Cl O-with ratiometric fluorescence changes.Compared with the probes depend on a single wavelength emission variation,it is better to overcome the interference of environmental factors.3.A benzothiazole derived thiosemicarbazone was synthesized and used as fluorescent probe for Zn²⁺ recognition.In PBS buffered?10 mM,pH = 7.4?water solution,L2 displays high selectivity to Zn²⁺ over other metal ions.The results indicate that the Zn²⁺ sensing event is very quick and can accomplish within 10 s,and with a detection limit of 1.42×10^-6M.These results manifest that L2 is practicable for simple Zn²⁺ detection.Simple test strips experiments evidenced the applicability of L2 for Zn²⁺ detection,in real water samples.4.A new 2-?2?-hydroxyphenyl?benzothiazole derived acylhydrazone compound?L3?was designed and synthesized.In ethanol solution,L3 exhibits a highly selective fluorescence response.The fluorescence titration of L3 with Al³⁺,disclosed that utilization of 5.5 equiv of Al³⁺ can reach saturation.Binding storichiometry studies show that L3 and Al³⁺,interacts with a 1:1 binding ratio.