Synthesis And Photochromic Properties Of Dithienylethene Axially Coordinated To Metal Porphyrins

Among various organic photochromic materials,dithienylethene is widely considered to be a new generation of photon storage media due to its excellent thermal stability and fatigue resistance.However,these photochromic materials keep bottleneck problems in the practical application,including low photon yield,poor fatigue resistance and the destruction of recorded information after read-out,so it is necessary to introduce other groups to solve these problems.In this paper the structure of the synthesized pyridyl dithienylethene was modified by making different metal porphyrins axially coordinated with it.The contents of this thesis are presented as follows:(1)The three target asymmetric dithienylethene were prepared via halogenation,Friedel-Crafts acylation,McMurry coupling,Suzuki coupling by using 2-methyl-thiophene as the starting material.Throughout the synthesis route,three target compounds have been obtained by simply changing the halogenated aromatics in the Sukuki coupling reaction in the last step.In this paper these target compounds are:pyridyl dithienylethene,aminophenyl dithienylethene,bromophenyl dithienylethene.(2)Photochromic properties of dithienylethenes from(1)were investigated,the experimental results indicate that they all possess good photochromic properties:the open and closed form can convert to each other upon irradiation of certain light,which has a good reproductivity;these three compounds also hold excellent thermal stability and fatigue resistance at room temperature.(3)Metal porphyrins Zn(?)MPDME,Co(?)MPDME,Mn(?)TPP were synthesized from hemin and tetraphenlporphyrin.This part is the preparation for the porphyrins incorporating into the dithienylethene.(4)The photochromic properties of Zn(?)MPDME-PyDTE,Co(?)MPDME-PyDTE,Mn(II)TPP-PyDTE were investigated in comparation with the UV-Vis spectra from(2).The results showed that the obvious red shift occurs in the UV-Vis spectra of the compound after modification,the wavelength distance of each two isomers becomes larger.To realize the nondestructive readout,the process of writing-reading-erasing should be independent of each other.It is found that only Mn(?)TPP-PyDTE can satisfy the above conditions and can be applied to non-destructive reading of information.