Chemical Research in Chinese Universities ›› 2020, Vol. 36 ›› Issue (5): 821-828.doi: 10.1007/s40242-020-9087-4

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Self-assembly Palladacycle Thiophene Imine Monolayer-Investigating on Catalytic Activity and Mechanism for Coupling Reaction

LI Lun1, XUE Xiaoxia1, SUN Yimeng1,2, ZHAO Wuduo1, LI Tiesheng1, LIU Minghua2,3, WU Yangjie1   

  1. 1. College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China;
    2. Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, P. R. China;
    3. Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
  • Received:2019-12-04 Revised:2020-01-08 Online:2020-10-01 Published:2020-10-01
  • Contact: LI Tiesheng, LIU Minghua, WU Yangjie E-mail:lts34@zzu.edu.cn;liumh@iccas.ac.cn;wyj@zzu.edu.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(No.21861132002) and the Natural Science Foundation of Henan Province, China(No.192102210046).

Abstract: An ordered cyclopallated thiophene imine self-assembly monolayer(Si@Pd3TI) was designed and fabricated. It was characterized by water contact angle(WCA), ultraviolet-visible spectroscopy(UV), cyclic voltammetry(CV), infrared(IR) spectrum, atomic force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS). Its ca-talytic performance for Suzuki coupling reaction and catalytic mechanism were systematic investigated. Si@Pd3TI was validated as a heterogeneous catalyst identified by poisoning tests, hot filtration test and three-phase test. The heterogeneous catalytic mechanism was investigated by WCA, UV, Raman spectrum(RS), AFM, XPS and density functional theory(DFT). The catalytic mechanism proceeded via surface-catalysis process, on which the Pd(II)/Pd(I)/Pd(0) synergistic active center acted likely as "multimetallic cluster". It played a great role for cataly-zing coupling reaction, in which the real active species was Pd(I).

Key words: Cyclopalladated imine, Thiophene, Coupling reaction, Self-assembly monolayer, Heterogeneous, Synergistic