Synthesis And Applications Of Specific Fluorescent Probes For Carbon Monoxide

As a kind of colorless,odorless and pungent poisonous gases,carbon monoxide exists widely in natural environment,industrial production and family life.Long-term exposure to carbon monoxide has been shown to have significant effects on the central nervous system,which leading to negative effects such as depression and memory loss.The organisms would die when carbon monoxide is present at high concentrations in the environment.So carbon monoxide is known as the "silent killer" because of its colorless,odorless,highly toxic nature.However,recent reports have demonstrated that carbon monoxide,as an important messenger molecule in living systems,plays an important role in many physiological and pathological processes.An imbalance of carbon monoxide in living systems can lead to a range of diseases.Therefore,the detection of carbon monoxide in the environment of living systems is of great significance.The development of suitable methods for carbon monoxide detection has become an important research topic.In this thesis,four carbon monoxide fluorescent probes with different functions were successfully designed and synthesized by using Intramolecular Charge Transfer(ICT)mechanism to detect carbon monoxide in living system.1.A long-wavelength colorimetric fluorescent probe LW-CO was successfully designed and synthesized by using tricyanofuran as fluorophore and allyl carbonate as the recognition receptor.Probe LW-CO successfully achieved the purpose of detecting CO,and the color of the solution changed significantly(from yellow to pink)after the reaction,which was able to achieve the purpose of naked eye observation with simple operation.Meanwhile,the probe can also recognize CO with high sensitivity,and the detection limit is 3.2 nM.On the basis of high sensitivity,the probe successfully achieved the fluorescence imaging study of intracellular exogenous CO.2.The fluorescent probe FR-CO was designed and synthesized by using rhodamine dyes as the fluorescence group of the molecule and allyl carbonate as the recognition receptor.The performance of the probe FR-CO was functionally optimized on the basis of the long emission wavelength,enabling the probe to achieve the goal of successfully targeting and locating in mitochondria.Similarly,the probe can also achieve the purpose of naked eye colorimetric detection of CO.By changing the color before and after the reaction from colorless to pink,the probe FR-CO can roughly determine the concentration of CO in the environment.3.A ratiometric fluorescent probe Ratio-CO was designed and synthesized with 4-hydroxy-1,8-naphthylimide as the fluorescence group and allyl ether as the recognition receptor.Probe Ratio-CO had an emission peak of 460 nm,but when CO was added into the system,the emission peak of the probe had a significant red shift,and a new emission peak was generated at 550 nm.The fluorescence spectra show a good isoemission point.This ratiometric result in the exclusion of external environmental factors can make the experimental results more accurate.At the same time,the probe also successfully realized the ratiometric fluorescence imaging of intracellular exogenous CO.4.Based on the mechanism of CO reduction from nitro to amino group,and the recognition receptor of 3-hydroxy-4-nitrobenzaldehyde,a novel near infrared fluorescent probe NIR-CO was designed and synthesized.Probe NIR-CO successfully achieved the purpose of detecting exogenous and endogenous CO in cells and zebrafish.The production of CO in glycosylated heme oxygenase was further investigated based on the change of CO concentration in the glycosylated biological system.To sum up,this thesis successfully synthesized four kinds of CO fluorescent probes with different functions: LW-CO,FR-CO,Ratio-CO and NIR-CO,and further experiments on the properties of the probes were performed.The results show that these four probes can achieve the purpose of detecting intracellular CO,and all of them show high sensitivity and fast response,providing good tools for the follow-up discussion of the concentration changes of CO in the living system.