Synthesis And Sensing Properties Of Coumarin Fluorescent Probes

Coumarin is a fluorophore with excellent luminescence properties.Due to its good water solubility,high fluorescence quantum yield,good photostability,and easy to derivatived or modified,coumarin was selected as the fluorophore in this paper.Three fluorescent probes for the detection of biothiols or hydrazine were synthesized.The specific work is as follows:(1)Using coumarin as the fluorophore and acryloyl chloride as the recognition group,the fluorescent probe SWJT-W1 for biothiols was designed and synthesized.The buffer solution of DMSO : PBS = 1 : 4 was used as detection solution.Due to the electron-withdrawing group malondicyano,addition reactions can occur between probe and three thiols.The optimal conditions for the reaction of SWJT-W1 with thiols were investigated,and the mechanism studies and Gaussian calculations were carried out.SWJT-W1 has good water solubility,low toxicity and cell membrane permeability,so SWJT-W1 was applied in Hep G2 cell imaging studies.(2)The fluorescent probe SWJT-W2 for hydrazine was designed and synthesized by using coumarin as the fluorophore and acetyl group as the recognition group.Meanwhile,a water-soluble indole salt was introduced into the coumarin skeleton to improve the water-solubility of the probe.The probe also reacts well in the DMSO/PBS system.The optimal conditions for the reaction were screened,and the reaction mechanism and the change of fluorescence intensity before and after the reaction were verified through round-bottom flask experiments and Gaussian calculations.Finally the probe was applied to the detection of hydrazine vapor by the obvious color changes.These results showed that SWJT-W2 can be used for the detection of hydrazine vapor.(3)On the basis of the above work,considering the emission wavelength of SWJT-W1 located in the visible light region and had the interference of background autofluorescence,the near-infrared group isophorone was introduced into the coumarin skeleton to make the emission wavelength reach the near-infrared region.Therefore,the near-infrared fluorescent probe SWJT-W3 was synthesized with acetyl group as the recognition group.After screening,SWJT-W3 reacted with hydrazine well in DMSO/PBS system.Spectral test showed that SWJT-W3 has a faster response time.The round-bottom flask experiments were performed to verify the reaction mechanism,and Gaussian calculations were carried out to determine the fluorescence properties of the corresponding compounds.Finally,it was applied to the detection of hydrazine vapor of environmental samples,and the color changes could be observed by the naked eye,indicating that SWJT-W3 could be used for the detection of hydrazine vapor.