Chinese Journal of Applied Chemistry ›› 2016, Vol. 33 ›› Issue (4): 442-451.DOI: 10.11944/j.issn.1000-0518.2016.04.150282

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Synthesis, Characterization and Photoisomerization Properties of Pseudostilbene Azobenzenes

SONG Xiumeia,FENG Zongcaia*(),WANG Zhaoyangc,CHEN Xiaolingb,LIANG Zhimeib,LIANG Yanyub   

  1. aDevelopment Center for New Materials Engineering & Technology in Universities of Guangdong,Industrial Technology Research Institute
    bSchool of Chemistry and Chemical Engineering,Lingnan Normal University,Zhanjiang,Guangdong 524048,China
    cSchool of Chemistry and Environment,South China Normal University,Guangzhou 510006,China
  • Received:2015-08-06 Accepted:2015-11-19 Published:2016-04-01 Online:2016-04-01
  • Contact: FENG Zongcai
  • Supported by:
    Supported by the Natural Science Foundation of Guangdong Province(No.S2011010001544, No.2014A030313429), the Bureau of Science and Technology of Zhanjiang Municipality(No.2014B01031, No.2015A02008)

Abstract:

A series of novel pseudostilbene azobenzenes was synthesized and their structures were characterized by FT-IR, NMR, MS(ESI) and elemental analysis. The photoisomerization properties and reversible cis/trans isomerization rate constants in solvent were measured via UV-Vis spectroscopy, as well as the fatigue resistance property in polymethyl methacrylate(PMMA) film was performed. The azobenzenes in ethyl acetate have the two bands of π-π* and n-π* inverted on the energy scale and π-π* and n-π* bands are practically superimposed. The isomerization rate constants range from 10-1 to 100 s-1. The trans to cis isomerization rate constants depend on the dipole-dipole interactions and molecular steric hindrance, with the dipole-dipole interactions having larger impact on monobromo-azobenzenes than dibromo-azobenzenes, and a reverse impact from molecular steric hindrances. The faster trans to cis transformation corresponds to the slower cis to trans transformation. The azobenzene has a good fatigue resistance to some extent in PMMA film.

Key words: pseudostilbene azobenzenes, azo coupling, photochromic, cis/trans isomerization, rate constant