Design,Synthesis And Performance Study Of Dithienylethene-based Tetraphenylporphyrin

Photochromic materials which can undergo reversible changes between two isomers up-on specific irradiation,are expected to be applied in ultrahigh-density erasable data storage systems.Among various photochromic compounds,dithienylethenes are most likely to be developed into optical memory media due to their favorable thermal stability and high fa-tigue-resistence.However,it is the primary problem to realize nondestructive readout while reading the stored data.Aiming at optical information processes,the fluorescence emission can be a promising signaling mode because the fluorescence signals can be readily and sensitively recognized.Porphyrins are known as natural molecules to exhibit characteristic S band in ul-traviolet region and Q band in visible region and they will emitluminescence upon specific excitation while dithinenylethene cannot fluoresce,so they can be a class of ideal luminescent materialsIn this paper,porphyrin unit was introduced into dithienylethene to realize nondestruc-tive readout.The main contents are as follows:(1)1,2-Bis(5-chloro-2-methyl-3-thienyl)cyclopentene was synthesized using 2-chloro-5-methylthiophene and glutaryl chloride as the starting materials via Friedel-Crafts acyl ation and McMurry coupling.At the same time,experimental conditions were discusse d in detail.(2)TPP-NH2 obtained by adopting TPP as the raw material which experiences nitration using fuming nitric acid and then reduction using SnCl2.The influencing factors of nitration were discussed and optimized in this paper.In additionTPP-NH2 was reduced to TPC-NH2 with diimide.(3)TPP-NH2 and DTE were used to prepare a dithienylethene-bridged tetraphenylpor-phyrin(DTE-TPP)where porphyrin macrocycle is attached to the end of DTE backbone through amide condensation and Suzuki reaction,and the structure of target compound was fully characterized by 1H NMR,13C NMR,MS and IR.Photochromic properties of the target compound,fatigue resistance and nondestructive readout capability were investigated by UV-Vis spectra and fluorescent emission spectroscopy.The UV-Vis spectra results indicated that DTE-TPP underwent bistable and reversible photochromic reactions under irradiation,which was repeated at least eight times between 254 and 660 nm light.The ring-opened form and ring-closed form of DTE-TPP exhibited great contrasts in fluorescence spectra(?ex=520 nm)so nondestructive readout method can be achieved.