Studies On The Syntheses And Properties Of Porphyrins Bearing Pyrene Or Phenazine Unit

Porphyrin oligomers or arrays that were linked by varied “bridges” are a class of organic functional molecules with special photophysical properties.These functional molecules exhibit different and novel properties compared with porphyrin monomers in light of the strong electron interaction between the bridges and the porphyrins moieties.The reported complexes were almost constructed by employing benzene,thiophene,pyrrole et al as linkage units,however the study of pyrene or phenazine as bridge linkagaes was relatively rare.We here prepared two novel porphyrin compounds linked by(hetero)aromatic groups.All of their structures were characterized by NMR,X-ray crystallographic analysis and Matrix-assisted laser desorption ionization time-of-flight(MALDI-TOF)mass spectrometry comprehensively,and their photophysical and electrochemical properties were primarily studied based on ultraviolet-vis absorption spectra,fluorescence spectra and cyclic voltammetry(CV)and differential-pulse voltammetry(DPV)experiments.This thesis contains three parties listed as follows:(1)A brief overview mainly on the pyrene-porphyrins and porphyrins containing nitrogen-heterocycles in recent decades.(2)Synthesis of pyrene-porphyrin compounds bridged by pyrene unit.Suzuki-Miyaura coupling of meso-boryl-10,15,-triaryl Ni(II)porphyrin with 1,3,6,8-tetrabromopyrene or meso-bromo-10,15,20-triaryl Ni(II)porphyrin with 1,3,6,8-tetraborylpyrene was carried out,resulting in two kinds of porphyrin-pyrene compounds 13 Ni and 14 Ni.Importantly,the structure of 14 Zn,a porphyrin tetramer,was confirmed by X-ray diffraction analysis,in which the porphyrin unit and the pyrene moiety adopt nearly perpendicular geometry.The UV/vis absorption spectra indicate that Q bands of these pyrene-porphyrins compounds are negligibly red-shifted,suggesting a weak conjugation present between the porphyrin and pyrene units.In addition,the energy transformation from the pyrene moiety to the porphyrin unit has been disclosed by fluorescence emission spectra.(3)Synthesis of phenazine-porphyrin compounds bridged by phenazine unit.Phenazine unit was successfully introduced into the meso-positions of porphyrins through the nucleophilic substitution reaction of 5-chloroporphyrins with 5,10-dihydrophenazine with the aid of NaH.Moreover,phenazine-fused porphyrin compounds were obtained by oxidation dehydrogenation.The UV/vis absorption spectra of phenazine-fused porphyrins 20 Ni and 22 Ni indicate that the absorptions of their Q bands are significant red-shifted in relative to compounds 18 Ni and 19 Ni.Simultaneously,electrochemical results imply the corresponding HOMO-LUMO gaps are more narrowed.All of these indicate the π system of phenazine-fused porphyrin compounds are effectively extended and the strong electron interaction present between phenazine unit and porphyrin unit.