Chem. J. Chinese Universities ›› 2009, Vol. 30 ›› Issue (8): 1605.

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Density Functional Studies of Magnetic Exchange of Biheteroatom 11-Heteropoly Complexes: [M(H2O)XW11O39]7-(X=Fe, Co; M=Co)

FANG Liang, GUAN Wei, YAN Li-Kai, SU Zhong-Min*   

  1. Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China
  • Received:2008-05-21 Online:2009-08-10 Published:2009-08-10
  • Contact: SU Zhong-Min. E-mail: zmsu@nenu.edu.cnKeggin
  • Supported by:

    国家自然科学基金(批准号: 20703008)和“长江学者和创新团队”发展计划(批准号: IRT0714)资助.

Abstract:

The magnetic exchange interactions for the biheteroatom 11-heteropoly complexes: [M(H2O)XW11O39]n-(Ⅰ: X=Fe, M=Co; Ⅱ: X=Co, M=Co) were investigated via density functional theory combined with broken-symmetry approach(DFT-BS) method. The calculated J values are -35 cm-1(Ⅰ) and -44 cm-1(Ⅱ), respectively, which show that antiferromagnetic exchange interactions exist in these complexes. The order of the absolute value of J is: |J(Ⅰ)|<|J(Ⅱ)|, indicating the increase of coupling interaction from system Ⅰ to Ⅱ. With the change of the heteroatom X via Fe(Ⅰ)→Co(Ⅱ), the spin densities on bridge oxygen atoms Ob and Ob2(O′b2) increase. Furthermore, from the comparison of BS magnetic orbitals in system Ⅰ and Ⅱ we find the overlap of relative orbitals in system Ⅱ enlarges. Consequently, a stronger antiferromagnetic coupling arises in system Ⅱ than in Ⅰ.

Key words: Keggin-type heteropolyoxometalate derivative; Magnetic exchange interaction; Magnetic coupling constant; Broken-symmetry approach; Density functional theory

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