Electron-withdrawing substituent position effect on the optoelectronic properties of new photochromic diarylethenes
Three new photochromic diarylethenes beating cyano groups at the ortho-, meta-, or para-positions of both terminal phenyl rings, namely 1, 2-bis (2-methyl-5-(2-cyanophenyl)-3-thienyl) perfluorocyclopentene (1a), 1, 2-bis (2-methyl-5-(3-cyanophenyl)-3-thienyl) perfluorocyclopentene (2a), and 1, 2-bis (2-methyl-5-(4-cyanophenyl)-3-thienyl) perfluorocyclopentene (3a), have been synthesized. The substituent position effects on their optoelectronic properties, including photochromism, fluorescence and electrochemical properties in solution, were investigated systematically. The molar absorption coefficient (ε=7.48×104Lmol-1cm-1), the absorption maxima and the quantum cyclization yield (φ0-c=0.53) of 3a are the biggest while its cycloreversion quantum yield (φc-0=0.004) is the smallest. In hexane, the fluorescent emission peaks of diarylethenes 1a, 2a and 3a showed a bathochromic shift upon increasing concentration. The oxidations of diarylethenes 1a, 2a and 3a are initiated at 1.85, 1.58 and 1.58V, respectively, which are higher than those of their closed-ring forms 1b, 2b and 3b (1.61, 1.43 and 1.49V, respectively). The results indicate that the optoelectronic features of diarylethenes 1, 2 and 3 are distinctly different, which may be attributed to the different electron-withdrawing ability and steric effect of cyano groups with different substituted positions.
G Liu S Z Pu C H Zheng Z G Le M B Luo
Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanch Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanch College of Biology, Chemistry and Material Science, East China Institute of Technology, Fuzhou 34400
国际会议
第二届功能原料国际研讨会(The 2rd International Symposium on Functional Materials)
杭州
英文
278-283
2007-05-16（万方平台首次上网日期，不代表论文的发表时间）