Design,Synthesis And Optical Property Studies Of Sulfur-containing BODIPY-based Fluorescent Probes For Reactive Oxygen Species Detection

Fluorescent probe is a kind of fluorescent analytical method that combines high sensitivity,high selectivity,and short response time.These characteristics make it popular among researchers.Fluorescent probes are widely used in many fields such as bio-imaging,gas detection,metal ion detection,and so on.Reactive oxygen species（ROS）is a class of substances that contain oxygen,have high chemical reactivity,and have a short life span.They are widely presented in the human body,and related to many physiological and pathological processes.Due to its high sensitivity,good selectivity,short response time and low damage to the body,it becomes an important method for detecting active oxygen.Most of the developed ROS detection fluorescence probes lack selectivity and instability,so it is necessary to develop a highly selective and stable ROS detection fluorescent probe.In the previous research of fluorescent probes,our research group found that the fluorescent properties of sulfur-containing fluorescent probes under the different oxidation states of sulfur atoms,namely thioether,sulfoxide and sulfone,have great changes.They are stable and has a good application prospect.Therefore,in order to develop a new high-selectivity and high-stability ROS detection probe,we have designed and synthesized a series of new sulfur-containing BODIPY-based fluorescent probes and studied their optical properties.This thesis mainly includes two types of BODIPY-based fluorescent probes.We divided those probes into five groups and compared their optical properties.Based on the singlet oxygen probe published by our group last year,we designed a new probe with some improvements.The first type is meso-aryl BODIPY probes,the second is 2-substituted BODPY probes.There are three groups in type 1,the compounds in this type showed no obvious fluorescent properties change among different oxidation states.The quantum yields of those having fluorine atoms on aryl ring compounds are higher than those compounds without fluorine.When thioether was located on the benzene ring at the meso-position of BODIPY,the change in the para-and meta-position of its substitution had substantially no effect on its fluorescent properties.The second type contained two groups,the triple bond compounds and non-triple bond compounds.Compared to the first type,we made the functional group at the 2position of BODIPY.Both of two groups have obvious color changes after oxidation,especially the fourth group,with a triple bond as linker,the color of sulfide-sulfoxide-sulfone is showed as pink-yellow-green.This means that carbon-carbon triple bond can be used to improve fluorescent properties of probes.Although,those two groups showed fluorescent change response to oxidation,in the selective experiment,they showed no respond to many kinds of reactive oxygen species,as H₂O₂,Cl O^-,·OH.Based on this discovery,combined with our research on singlet oxygen probes,we designed and started the synthesis of the new generation of singlet oxygen probes.These probes are in modified chemical structure of the previous generation probes and work on“6-endo-tet”mechanism.At present,we just finished a small part synthesis work and tested for oxidation reaction.The results show that the probe has a certain response to singlet oxygen,but its specific selectivity and reactivity need to be verified by subsequent experiments.In summary,five sets of sulfur-containing fluorescent probes have been designed and synthesized.By analyzing the optical characteristics of these probes,we found that in the current model,the substitution at position 2 of the BODIPY structure is better than the substitution at the 8 position.The carbon-carbon triple bond could be used to improve the fluorescent properties of the probe.The fluorescent probe based on the previous generation singlet oxygen has a certain response to singlet oxygen.