Chemical Research in Chinese Universities ›› 2015, Vol. 31 ›› Issue (4): 597-602.doi: 10.1007/s40242-015-5004-7

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DFT Studies on Second-order Nonlinear Optical Properties of a Series of Axially Substituted Bis(salicylaldiminato) Zinc(II) Schiff-base Complexes

LIU Chunguang1,2, ZHANG Dingfan1, GAO Mingli1, LIU Shuang1   

  1. 1. College of Chemical Engineering, Northeast Dianli University, Jilin 132012, P. R. China;
    2. Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China
  • Received:2015-01-04 Revised:2015-01-29 Online:2015-08-01 Published:2015-03-30
  • Contact: LIU Chunguang E-mail:liucg407@163.com
  • Supported by:

    Supported by the National Natural Science Foundation of China(No.21373043), the Chinese Postdoctoral Science Foundation(No.2013M540261), the Scientific Research Fund for Doctor of Northeast Dianli University, China(No.BSJXM-201110) and the Innovation Fund for Graduate Student of Northeast Dianli University, China.

Abstract:

Coordination of an axial ligand to metal center to enhance the second-order nonlinear optical(NLO) response of a two-dimensional bis(salicylaldiminato) zinc(II) Schiff-base complex is an unprecedented model. The second-order NLO responses of a series of axially substituted bis(salicylaldiminato) zinc(II) Schiff-base complexes were explored according to the finite field(FF) method at CAM-B3LYP/6-31+G(d) level(LANL2DZ basis set for metal atoms). The results show that the second-order NLO properties can be effectively tuned by exchanging the donor and accepter of the axial ligand and extending the length of the conjugated bridge along the axial direction. A system involving the electron acceptor along the appropriate direction has a large three-dimensional second-order NLO response. Meanwhile, time dependent density functional theory(TD-DFT) method was employed to calculate the physical parameters of excited states. The results show that the Y- and Z-polarized transitions of the zinc(II) Schiff-base complex are the first and second excited states, respectively, and have a low-lying excited energy. Although the X-polarized transition has a high excited energy, the large oscillator strength indicates that it will significantly contribute to the second-order NLO response.

Key words: Schiff base, Zinc(II) complex, Nonlinear optical property, Axial ligand, Density functional theory