Field-Induced Slow Magnetic Relaxation in an Octacoordinated Fe(II) Complex with Pseudo-D2d Symmetry: Magnetic, HF-EPR, and Theoretical Investigations

Guo Ling Li; Shu Qi Wu; Li Fang Zhang; Zhenxing Wang; Zhong Wen Ouyang; Zhong Hai Ni; Sheng Qun Su; Zi Shuo Yao; Jun Qiu Li; Osamu Sato

doi:10.1021/acs.inorgchem.7b00765

Field-Induced Slow Magnetic Relaxation in an Octacoordinated Fe(II) Complex with Pseudo-D_2d Symmetry: Magnetic, HF-EPR, and Theoretical Investigations

Guo Ling Li, Shu Qi Wu, Li Fang Zhang, Zhenxing Wang, Zhong Wen Ouyang, Zhong Hai Ni^*, Sheng Qun Su, Zi Shuo Yao, Jun Qiu Li, Osamu Sato

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

25 Citations (Scopus)

Abstract

An octacoordinated Fe(II) complex, [Fe^II(dpphen)₂](BF₄)₂·1.3H₂O (1; dpphen = 2,9-bis(pyrazol-1-yl)-1,10-phenanthroline), with a pseudo-D_2d-symmetric metal center has been synthesized. Magnetic, high-frequency/-field electron paramagnetic resonance (HF-EPR), and theoretical investigations reveal that 1 is characterized by uniaxial magnetic anisotropy with a negative axial zero-field splitting (ZFS) (D ≈ -6.0 cm^-1) and a very small rhombic ZFS (E ≈ 0.04 cm^-1). Under applied dc magnetic fields, complex 1 exhibits slow magnetic relaxation at low temperature. Fitting the relaxation time with the Arrhenius mode combining Orbach and tunneling terms affords a good fit to all the data and yields an effective energy barrier (17.0 cm^-1) close to the energy gap between the ground state and the first excited state. The origin of the strong uniaxial magnetic anisotropy for 1 has been clearly understood from theoretical calculations. Our study suggests that high-coordinated compounds featuring a D_2d-symmetric metal center are promising candidates for mononuclear single-molecule magnets.

Original language	English
Pages (from-to)	8018-8025
Number of pages	8
Journal	Inorganic Chemistry
Volume	56
Issue number	14
DOIs	https://doi.org/10.1021/acs.inorgchem.7b00765
Publication status	Published - 17 Jul 2017
Externally published	Yes

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title = "Field-Induced Slow Magnetic Relaxation in an Octacoordinated Fe(II) Complex with Pseudo-D2d Symmetry: Magnetic, HF-EPR, and Theoretical Investigations",

abstract = "An octacoordinated Fe(II) complex, [FeII(dpphen)2](BF4)2·1.3H2O (1; dpphen = 2,9-bis(pyrazol-1-yl)-1,10-phenanthroline), with a pseudo-D2d-symmetric metal center has been synthesized. Magnetic, high-frequency/-field electron paramagnetic resonance (HF-EPR), and theoretical investigations reveal that 1 is characterized by uniaxial magnetic anisotropy with a negative axial zero-field splitting (ZFS) (D ≈ -6.0 cm-1) and a very small rhombic ZFS (E ≈ 0.04 cm-1). Under applied dc magnetic fields, complex 1 exhibits slow magnetic relaxation at low temperature. Fitting the relaxation time with the Arrhenius mode combining Orbach and tunneling terms affords a good fit to all the data and yields an effective energy barrier (17.0 cm-1) close to the energy gap between the ground state and the first excited state. The origin of the strong uniaxial magnetic anisotropy for 1 has been clearly understood from theoretical calculations. Our study suggests that high-coordinated compounds featuring a D2d-symmetric metal center are promising candidates for mononuclear single-molecule magnets.",

author = "Li, {Guo Ling} and Wu, {Shu Qi} and Zhang, {Li Fang} and Zhenxing Wang and Ouyang, {Zhong Wen} and Ni, {Zhong Hai} and Su, {Sheng Qun} and Yao, {Zi Shuo} and Li, {Jun Qiu} and Osamu Sato",

note = "Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",

year = "2017",

month = jul,

day = "17",

doi = "10.1021/acs.inorgchem.7b00765",

language = "English",

volume = "56",

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journal = "Inorganic Chemistry",

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T1 - Field-Induced Slow Magnetic Relaxation in an Octacoordinated Fe(II) Complex with Pseudo-D2d Symmetry

T2 - Magnetic, HF-EPR, and Theoretical Investigations

AU - Li, Guo Ling

AU - Wu, Shu Qi

AU - Zhang, Li Fang

AU - Wang, Zhenxing

AU - Ouyang, Zhong Wen

AU - Ni, Zhong Hai

AU - Su, Sheng Qun

AU - Yao, Zi Shuo

AU - Li, Jun Qiu

AU - Sato, Osamu

PY - 2017/7/17

Y1 - 2017/7/17

N2 - An octacoordinated Fe(II) complex, [FeII(dpphen)2](BF4)2·1.3H2O (1; dpphen = 2,9-bis(pyrazol-1-yl)-1,10-phenanthroline), with a pseudo-D2d-symmetric metal center has been synthesized. Magnetic, high-frequency/-field electron paramagnetic resonance (HF-EPR), and theoretical investigations reveal that 1 is characterized by uniaxial magnetic anisotropy with a negative axial zero-field splitting (ZFS) (D ≈ -6.0 cm-1) and a very small rhombic ZFS (E ≈ 0.04 cm-1). Under applied dc magnetic fields, complex 1 exhibits slow magnetic relaxation at low temperature. Fitting the relaxation time with the Arrhenius mode combining Orbach and tunneling terms affords a good fit to all the data and yields an effective energy barrier (17.0 cm-1) close to the energy gap between the ground state and the first excited state. The origin of the strong uniaxial magnetic anisotropy for 1 has been clearly understood from theoretical calculations. Our study suggests that high-coordinated compounds featuring a D2d-symmetric metal center are promising candidates for mononuclear single-molecule magnets.

AB - An octacoordinated Fe(II) complex, [FeII(dpphen)2](BF4)2·1.3H2O (1; dpphen = 2,9-bis(pyrazol-1-yl)-1,10-phenanthroline), with a pseudo-D2d-symmetric metal center has been synthesized. Magnetic, high-frequency/-field electron paramagnetic resonance (HF-EPR), and theoretical investigations reveal that 1 is characterized by uniaxial magnetic anisotropy with a negative axial zero-field splitting (ZFS) (D ≈ -6.0 cm-1) and a very small rhombic ZFS (E ≈ 0.04 cm-1). Under applied dc magnetic fields, complex 1 exhibits slow magnetic relaxation at low temperature. Fitting the relaxation time with the Arrhenius mode combining Orbach and tunneling terms affords a good fit to all the data and yields an effective energy barrier (17.0 cm-1) close to the energy gap between the ground state and the first excited state. The origin of the strong uniaxial magnetic anisotropy for 1 has been clearly understood from theoretical calculations. Our study suggests that high-coordinated compounds featuring a D2d-symmetric metal center are promising candidates for mononuclear single-molecule magnets.

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Field-Induced Slow Magnetic Relaxation in an Octacoordinated Fe(II) Complex with Pseudo-D_2d Symmetry: Magnetic, HF-EPR, and Theoretical Investigations

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