Research On The Optical Properties And Applications Of Porphyrin Compounds

Porphyrin is the generic term for a series of compounds which are formed by other functional groups replacing the hydrogen of ?,? or meso position of its parent porphin ring.Porphyrins and their derivatives are highly conjugated macrocyclic compounds and widely exist in nature,such as heme,which has the function of carrying oxygen,participating in photosynthesis magnesium porphyrin.Because of the 16 centers,18? electrons conjugate planar structure and smaller electronic energy level gap between the frontier molecular orbital energy levels HOMO to LUMO(about 2.7 e V)of the parent porphin ring,therefore,it has stable physical and chemical properties,easy modification,and excellent photoelectric properties.As a result,it is widely used in medicine,photoelectric material,dye-sensitised solar cells,synthesis of drug,simulating of natural products and the field of fluorescence analysis.Density functional theory(DFT)is a kind of new theory,which is proposed to study the ground state properties of multi-particle systems in quantum chemistry calculation.The most important advantage is that it adopted the electron density of the molecular structure instead of the wave function.As a result,the schr?dinger equation was solved.It not only can help people study the structure and properties of multi-particle systems,but also can calculate some vibration spectra related to atomic physics,catalytic activity,stability,routes of chemical reactions and other issues.With the development of research on the quantum chemistry calculation,the time-dependent density functional theory(TDDFT)is another method that opened up a train of thought for researchers.It is important that TDDFT discussed the excited state molecules' properties using the density functional method,rather than only study the ground state molecules' properties.In this thesis,we discussed the relationship between the structure and properties of the porphyrins and their derivatives based on the fluorescence analysis and DFT theory to study.There are four parts in this thesis,and the main research contents are as follows:Chapter one: Introduction.This chapter summarized the structural characteristics and properties of porphyrins and their derivatives,methods ofsynthesis and application in our society.We also discussed the development of fluorescence analysis and the principles of fabricating the fluorescence sensors.Lastly,it was briefly described of the generation and development of the density functional theory(DFT)and its applications for studying of the properties of the porphyrins and their derivatives.Chapter two: Theoretical study of the optical properties of a series of porphyrins and their derivatives.This chapter studied the ground state and excited state properties of six kinds of porphyrins obtained using the DFT/TD-DFT/B3LYP/6-31G(d)method.First,we used the method to optimize the ground state structures of the porphyrins,comparing them with the structural parameters and orbital properties of porphyrins of different substituents.And then,the TD-DFT/B3LYP/6-31G(d)method was utilized to study the excited state properties of the porphyrins,concluding with the substituting effect on the excited state properties of the porphyrins.Chapter three: Design of a novel naked-eye and turn-on fluorescence sensor based on the 5,10,15,20-(4-sulphonatophenyl)porphyrin(TPPS4)-Hg2+ system:monitoring of glutathione(GSH)in real samples and DFT calculation.In this chapter,we synthesized firstly a kind of excellent water-soluble TPPS4,and characterized the structure of TPPS4 using nuclear magnetic resonance hydrogen(1HNMR),FT-IR spectrometry,Uv-vis and FL spectrometry.Based on the strong red fluorescence of TPPS4,we fabricated a novel fluorescence sensor based on the TPPS4-Hg2+ system for sensitively investigating GSH in real samples.Furthermore,density functional theory(DFT)was combined with experiment.As a result,it was achieved successfully to detect GSH by fluorescence method.Chapter four: Based on TAPP preparation and “turn-off” typed of fluorescence sensor for detecting of hydrogen peroxides(H2O2)and glucose in real samples.In this chapter,we synthesized TAPP by an efficient method to increase the yield,and characterized the structure of TAPP using nuclear magnetic resonance hydrogen(1HNMR),FT-IR spectrometry,Uv-vis spectrometry.And then,we also fabricated a novel fluorescence sensor based on the excellent fluorescent performance of TAPP for detecting hydrogen peroxides(H2O2)and glucose in real samples.