Chinese Journal of Applied Chemistry

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Synthesis, Crystal Structure and Isomerization Property of 3′,5′-Dibromo-3-methoxy-4-hydroxyazobenzene

SONG Xiumei1,2, FENG Zongcai1*, CHEN Jianqiao3, WANG Zhaoyang2, FENG Cuijuan1, LU Yangli1   

  1. (1.Development Center for New Materials Engineering & Technology in Universities of Guangdong,Industrial Technology Institute,Zhanjiang Normal College,Zhanjiang 524048,China;
    2.School of Chemistry and Environment,South China Normal University,Guangzhou 510006,China;
    3.Faculty of Science,Shantou Polytechnic,Shantou 515078,China)
  • Received:2014-01-02 Revised:2014-03-10 Published:2014-10-09 Online:2014-10-09
  • Contact: feng zongcai

Abstract: Starting from 4-amino nitrobenzene, 3′,5′-dibromo-3-methoxy-4-hydroxyazobenzene 6 was synthesized via sequential reactions of dibromination, diazotization deamination, nitro-reduction and diazo coupling. Polymethyl methacrylate(PMMA) films containing azobenzene 6 were obtained by a physical doping process. The structure of the title compound was characterized by elemental analysis, FT-IR, MS(ESI), 1H NMR, 13C NMR, MS, especially by the X-ray single crystal diffraction. The crystal crystallizes in the monoclinic space group C2/c, with a=1.6182(3) nm, b=0.81847(16) nm, c=2.1945(4) nm, β=102.819(2) °, V=2.8342(10) nm3, Z=8, Dc=1.809 g/cm3, μ=5.719 mm-1, F(000)=1504, R1=0.0366 and ωR2=0.0764. The title compound exists in the trans-form. The intermolecular hydrogen bonds and π-π stacking between benzene rings contributes to one-dimensional infinite chain structure along b axis. By UV-Vis spectroscopy method, the reaction rate constants for trans-cis photoisomerization and cis-trans thermal back-isomerization are at the range of 10-1~10-2 min-1.

Key words: dibromo-methoxy-hydroxyazobenzene, crystal structure, trans-cis photoisomerization, thermal back-isomerization, rate constant

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