Photochromism of diarylethenes containing dithieno[3,2-b:2′,3′-d]thiophene

Novel photochromic diarylethene and diarylethene dimer containing dithieno[3,2-b:2′,3′-d]thiophene were designed and synthesized to compare their photochromic properties. Photochromism in solution and in the crystalline phase, fluorescence, electrochemical character, and theoretical calculations of the two compounds were studied. Both of them showed remarkable photochromic performance in the solution as well as in the crystalline phase. In the photostationary state, the conversion ratio in solution and in the crystalline phase from open-ring isomer to closed-ring isomer under irradiation was estimated by HPLC analysis. However, for diarylethene dimer, it showed higher fluorescent modulation efficiency while its photocyclization could only take place at one of the two diarylethene units due to the intramolecular excited energy transfer.

► Novel photochromic diarylethene and its dimer containing Dithieno[3,2-b:2′,3′-d]thiophene were designed and synthesized. ► Photochromism, fluorescence, electrochemical characters, quantum yields, theoretical calculations and conversion ratio were carried out. ► Both of them showed remarkable photochromic performance in solution as well as in the crystalline phase.