1. Field-Induced Slow Magnetic Relaxation in an Octacoordinated Fe(II) Complex with Pseudo-D2d Symmetry: Magnetic, HF-EPR, and Theoretical Investigations
- Author
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Guo Ling Li, Zhenxing Wang, Zi Shuo Yao, Jun Qiu Li, Zhong Hai Ni, Sheng Qun Su, Shu Qi Wu, Li-Fang Zhang, Zhong Wen Ouyang, and Osamu Sato
- Subjects
Arrhenius equation ,Condensed matter physics ,010405 organic chemistry ,Chemistry ,Band gap ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Magnetic field ,law.invention ,Inorganic Chemistry ,symbols.namesake ,Magnetic anisotropy ,law ,Excited state ,Magnet ,symbols ,Physical and Theoretical Chemistry ,Electron paramagnetic resonance ,Ground state - 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.
- Published
- 2017