Chem. J. Chinese Universities ›› 2018, Vol. 39 ›› Issue (4): 743.doi: 10.7503/cjcu20170495

• Physical Chemistry • Previous Articles     Next Articles

Adsorption of Iodoperfluoroalkanes on Tetrabutyl Ammonium Halide by Halogen Bond

YAN Xiaoqing, LIU Qiushuang, LIU Yunfeng, NIU Qiao*()   

  1. School of Public Health, Shanxi Medical University, Taiyuan 030001, China
  • Received:2017-07-21 Online:2018-04-10 Published:2018-03-27
  • Contact: NIU Qiao E-mail:niuqiao55@163.com
  • Supported by:
    † Supported by the National Natural Science Foundation of China(No.81502851), the China Postdoctoral Science Foundation(No.2014M561208) and the Startup Foundation for Doctors of Shanxi Medical University, China(No.055235)

Abstract:

The adsorption of 1,2-diiodotetrafluoroethane(C2F4I2) on tetrabutyl ammonium iodide(Bu4N+I-) was analyzed by IR, UV and 19F NMR spectroscopies. The according spectrum changes of IR, UV and 19F NMR indicated that halogen bond complexes were formed in solution, which demonstrated that the adsorption was due to the C-I…I- halogen bonding interactions. The adsorptivities of five quaternary ammonium salts were compared and the experiment results showed that adsorptivity was Bu4N+Cl->Bu4N+Br->Bu4N+I-. Hexadecyl trimethyl ammonium chloride and hexadecyl trimethyl ammonium bromide, which have long alkyl chain, had absolutely no adsorption to C2F4I2. It is probably because that the long alkyl chains prevented halide anion from closing to C2F4I2. The adsorption of four iodoperfluoroalkanes(C4F8I2, C4F9I, C6F12I2, C6F13I) by Bu4N+Cl- salt were investigated. The results showed that although halogen bonds in the monoiodoperfluoroalkanes(monoiodo-PFAs) complexes were stronger than those in the diiodoperfluoroalkanes(diiodo-PFAs) complexes as estimated by Raman spectra in solution, the adsorptivities of Bu4N+Cl- for the diiodo-PFAs were stronger than those for the monoiodo-PFAs at the solid/liquid interface because the odds of forming halogen bond of diiodo-PFAs is double that of monoiodo-PFAs. Besides, it was found that the formation of halogen bonds could enhance the Raman signals of iodoperfluoroalkanes.

Key words: Halogen bond, Iodoperfluoroalkane, Tetrabutyl ammonium halide, Halide anion, Adsorption

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