Study On The Synthesis And Properties Of Corroles

Corroles are a class of macrocycle compounds containing four conjugated pyrroles.These compounds have similar molecular structures to porphyrins,but also have certain particularities as compared to the corresponding porphyrins.Therefore, the corroles have unique properties of photochemistry,electrochemistry,photophysics and photobiology,and have a lot of potential applications in the field of functional materials,biomedicine,phtocatalysts or electrocatalysts.In this thesis,the structures,properties,the main synthetic methods and the progress of research and applications for the corrole and metallocorroles were introduced.Five corroles,i.e.triphenylcorrole 1,tri-4-chlorophenylcorrole 2, tri-2-nitrophenylcorrole 3,tri-3-nitrophenylcorrole 4 and tri-4-nitrophenylcorrole 5 were synthesized by an improved Lindsey method in the mixture of ethanol and H₂O. The sythesized corroles were characterized by elemental analysis,FT-IR,UV-Vis,1^H NMR spectroscopies and electrochemistry.UV-visible spectra of the corroles were measured in eleven different nonaqueous solvents as well as in two solutions of neat concentrated acid.The effect of solvent acidity or basicity on the spectra and existing forms of the corroles was discussed. The results indicate that the products are the protonated corroles in concentrated acetic acid or in CH₂Cl₂ containing 0.10 mol/L H₂SO₄ or HClO₄.The deprotonated corroles were formed in basic solvents.The protonated corroles may decompose due to the conjugated macrocycle being broken in the presence of concentrated strong acids.The protonation constants(logK) of corroles were determined based on the spectral changes obtained during a titration with TFA in PhCN.The effect of environmental illumination on the UV-visible spectra of corroles have been studied.The spectra of compounds 1 and 2 decreased in intensity under the natrual light in CH₂Cl₂ indicating that both 1 and 2 are not stable and could easily occur the reactions of decomposion and breaking macrocycle under the given experimental conditions.However,environmental illumination only has a weak effect on the spectra of the compounds 3,4 and 5 with nitro substituents under the same experimental conditions.The results indicate that the nitro substituents may lead to corroles more stable.The fluorescence spectra of the corroles were measured in CH₂Cl₂ and DMF and the results indicate that all investigated corroles possess good fluorescence properties. In addition,the electrochemical properties of the corroles were also studied by cyclic voltammetry in DMF containing 0.1 mol/L tetra-n-butylammonium perchlorate.Two or three reductions can be observed for these corroles under the given experimental conditions.