Affiliation:
1. School of Pharmacy Jining Medical University Rizhao Shandong 276826 P. R. China
2. Division of Materials Science Nara Institute of Science and Technology (NAIST) Ikoma Nara 630–0192 Japan
Abstract
AbstractPhotoinduced tuning of aromaticity and correlative molecular properties has attracted enormous interest in recent years both for modulating photochromism properties and designing novel photochromic materials. Here, we report the synthesis and photochemical characterization of diaryl[5]helicene‐based diarylethene molecular switches. 3,4‐Bis(2,4‐dimethyl‐5‐phenylthiophen‐3‐yl)dibenzo[c,g]phenanthrene derivative 1 a showed no photochromic reaction, whereas 3,4‐bis(2‐methyl‐5‐phenylthiophen‐3‐yl)dibenzo[c,g]phenanthrene derivative 2 a and 3,4‐bis(5‐methyl‐2‐phenylthiazol‐4‐yl)dibenzo[c,g]phenanthrene derivative 3 a exhibited reversible photochromism in different aprotic solvents with specific light irradiation. Meanwhile, the diarylethene compounds 2 a and 3 a underwent turn‐off mode fluorescence photoswitching together with photoisomerization upon light irradiation. Remarkably, the photoinduced changes in the aromaticity of [5]helicene as a central ethene bridge along with the relative smaller activation energy and higher frequency factor facilitated the thermal bleaching rates of diarylethene switches 2 and 3 in solution. This research provides new insight for designing aromatic diarylethene photoswitches for reversible fluorescence switching, photoinduced changes in aromaticity and further fast thermal back reactions.
Funder
Natural Science Foundation of Shandong Province
National Outstanding Youth Science Fund Project of National Natural Science Foundation of China
Japan Society for the Promotion of Science
Subject
General Chemistry,Catalysis,Organic Chemistry