Study On Electrochemiluminescence System Of Porphyrin And Their Composites

Chemiluminescence is a phenomenon of light radiation that appears in the process of chemical reactions.This phenomenon is also widely exist in many living organisms,such as fireflies and marine organisms.As an important branch of chemiluminescence,electrochemiluminescence（ECL）is undoubtedly important,which is a special kind of chemiluminescence triggered by voltage.In ECL,the luminophors will product an excited state through an electrochemical oxidation-reduction reaction,and the energy is released in the form of light when the excited state returns to the ground state,which is ECL.Compared with chemiluminescence,it has the following advantages:it does not require an additional light source,requires a small amount of luminescent reagent,high sensitivity,reproducibility,good selectivity,low detection limit,and wide range of linear detection.In recent years,ECL technology has been developed rapidly,and usually are used for biosensors,medical detection and other fields.However,although more and more ECL luminophors are being continuously developed,the improvement of the luminous efficiency of ECL luminophors has always been a key challenge and difficult point for researchers to explore.Porphyrins are commonly used as organic compounds and electrochemiluminescent agents,which is stand out among the luminaries of organic compound due to their simple synthesis steps,easy modified,good biocompatibility,and excellent photoelectric properties.Many researches have been committed to research porphyrins and its related applications in the field of electrochemistry and electrochemiluminescence（ECL）.However,it is easy to aggregate in aqueous solution and have weak luminescence performance of ECL research.It is urgent to improve the ECL intensity of porphyrins and solve the aggregation of porphyrin in the field of ECL.Therefore,this article mainly focuses on the related research and application of the above-mentioned problems.The three parts of the research are as follows:Part 1:Electrochemiluminescence study of tetracarboxyphenyl porphyrin/ionic liquid self-assembled compositesIn this chapter,the electrochemiluminescence（ECL）performance about tetracarboxyphenyl porphyrin（TCPP）after modification is mainly studied by modifying porphyrin compounds.Combine tetracarboxyphenyl porphyrin（TCPP）and ionic liquid 1-butyl-3-methylimidazole hexafluorophosphate（BMIMPF₆）through amide reaction to obtain amide bond to form a new composites,which is tetracarboxyphenylPorphyrin/ionicliquidself-assembledcomposites（TCPP/BMIMPF₆）,the electrochemical and ECL performance of TCPP/BMIMPF₆composite material was studied,and the ECL mechanism of its luminescence system was further explored.In this experiment,the TCPP/BMIMPF₆self-assembled composites was first constructed,and then make use of BMIMPF₆sensitization and the interaction between TCPP and BMIMPF₆,which not only solves the aggregation problem of porphyrin caused byπ-πaccumulation,but also greatly improved the luminescence performance of porphyrin.Therefore,using the experimental program designed in this experiment makes the research of porphyrin has far-reaching significance and broadens the research of porphyrin in the field of ECL.Part 2:Using solvent effect to improve the ECL of porphyrinsAs a typical photosensitizer,porphyrin has been studied by many scientists in the field of ECL.Among them,improving the luminescence performance of porphyrin has been a breakthrough point in broadening the application field of porphyrin.Therefore,in this part of the work,we use the unique properties of deuterated water（D₂O）,and tetracarboxyphenyl porphyrin（TCPP）and deuterium oxide（D₂O）are used to construct a luminescent system.When heavy water（D₂O）is added to the TCPP aqueous solution,H/D exchange occurs,which reduces the radiation-free relaxation rate of singlet oxygen generated by porphyrin,thereby prolonging the lifetime,increasing the quantum yield,and enhancing the performance of ECL.Compared with other methods of constructing composite materials,this strategy is simpler and less consumable.Part 3:Electrochemiluminescence study based on tetracarboxyphenyl porphyrin/indole compositesIn this part of the work,the ECL system of a novel composites（TCPP/Indol）was constructed by hydrogen bonding between tetracarboxyphenyl porphyrin（TCPP）and indole（Indol）,which avoids TCPP forms agglomerates in the water phase and causes the problem of weak ECL performance.When potassium persulfate（K₂S₂O₈）is used as a co-reactant,it has high ECL strength and stability.