Synthesis And Properties Of New Diarylethenes Bearing An Indazole/Quinoline Moiety

Photochromic diarylethenes,which have shown potential application value in molecular switch,optical memory,erase duplication,high-density optical information storage and so on,have been one of the most potential materials among all the reported photochromic compounds because of their remarkable fatigue resistance and good thermal stability.Therefore,the design and synthesis of new diarylethenes are still a hot topic nowadays.The compounds in this paper were synthesized from two aspects.The first categories contain a total of eight new diarylethenes,which were designed by the conventional methods.In these parts,we focused on the diarylethenes photochromism,fluorescent molecules switches,fatigue resistance and thermal stability.The second categories contain a total of two new diarylethenes,which were designed by introducing the quinoline unit into diarylethenes.The contents and results are as follows:1.In this research,the general situation and development of the diarylethenes were reviewed.And then,the target of our research was brought out combined with the current status.2.A new class of photochromic diarylethenes with both azaindole and thiophene moieties were firstly synthesized to investigate the effects of the substituents on their photochromic behaviors,and their structures were determined by single crystal X-ray diffraction analysis.Whether the electron-donating substituents or the electron-withdrawing groups can significantly enhanced their cyclization quantum yields and the molar absorption coefficient of their opend-ring isomers.Moreover,the compound of DT-3 has the best thermal stability and fatigue resistance and the highest fluorescence intensity in these five compounds.3.In this part,there unsymmetrical isomeric diarylethenes bearing a cyano group at either the para-,meta-,or ortho-positions of the terminal benzene ring were synthesized.It has been demonstrated that the electron-withdrawing cyano group induced different properties,such as absorption wavelength,the molar absorption coefficient and quantum yields of cyclization and cycloreversion,which were in the order of para-<meta-<ortho-substitution by the cyano group.However,meta-substitution DT-6 has the best thermal stability and DT-8 has the best fatigue resistance in these three compounds.Moreover,these three compounds showed favorable photochromic and fluorescence properties4.Two photochromic diarylethenes with the quinoline unit were designed and synthesized(DT-9 and DT-10).Because these two compounds had the same order towards ions selectivity and the fluorescence switch of DT-9 was better than that of DT-10,we mainly talked about the ions selectivity of DT-9.The results revealed that the two compounds showed the favorable photochromic in acetonitrile,as did DT-9 in crystalline phase.The compounds of DT-9 can sever as fluorescent sensor for recognition of Zn2+ and F-ions under the same conditions,respectively.It exhibits highly selective fluorescent sensor for Zn2+,avoiding the interference of Cd2+.This diarylethene also is a fluorescent sensor for detection of F-with high selectivity in acetonitrile.The complex ratio of DT-9 and F-was 1:1 with the bond of the-NH.