一个阿佐芬因基桥 Fe2 单分子磁铁,具有记录磁交换合的磁性交换合
Ie-Rang Jeon1, Jesse G Park, Dianne J Xiao
1Department of Chemistry, Northwestern University , Evanston Illinois 60208-3113, United States.
Journal of the American Chemical Society
|October 30, 2013
概括
研究人员创造了一个新的铁复合体与阿佐因连接体. 这个复合体表现出非常强的磁交换合,这是单分子磁铁的记录,为先进的磁性材料铺平了道路.
科学领域:
- 协调化学 协调化学
- 材料科学 材料科学 材料科学
- 磁力学 磁力学 是一种
背景情况:
- 单分子磁铁 (SMM) 是具有磁性特性的分子,对于数据存储和量子计算至关重要.
- 开发具有强磁交换合的SMM是提高其性能和稳定性的关键.
研究的目的:
- 为了合成和表征一种新型的铁复合物与阿佐因连接体.
- 为了研究复杂的缩小形式的磁性和交换合的特性.
- 为了评估其作为单分子磁铁的潜力.
主要方法:
- 铁复合物的合成 [(TPyA) 2Fe (((II) 2 (((NPh) L ((2-)))) ] ((2+).
- 一个电子的还原形成 [(TPyA) 2Fe ((II) 2 (((NPh) L ((3-•)))) ](+).
- 用X射线衍射和Mössbauer光谱进行结构和电子确认.
- 测量直流和交流磁性易感度,以确定磁性和旋转放松障碍物的磁性.
主要成果:
- 复合物的还原产生了一个具有S = 1/2根性质的桥接联体.
- 在Fe (II) 中心 (S=2) 和激素连接体之间进行极强的直接反铁磁交换.
- 减少复合体表现出单分子磁铁行为,具有显著的旋转放松屏障 (U(eff) = 50(1) cm(-1)).
结论:
- 合成的铁复合体在单分子磁体中表现出前所未有的强磁交换合.
- 这一发现代表了分子磁力学领域的重大进展.
- 该综合体对未来在高密度数据存储和量子信息处理方面的应用具有前景.
相关概念视频
01:31Ferromagnetism
2.8K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.8K
01:17Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
2.6K
Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
2.6K
03:02Colors and Magnetism
12.1K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.1K
02:42Valence Bond Theory
8.9K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.9K
01:26Diamagnetism
2.8K
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
2.8K
01:30Paramagnetism
2.4K
Paramagnets are materials with unpaired electrons that possess a finite magnetic moment. In the absence of a magnetic field, these moments are randomly oriented, and thus the net moment is zero. Under an external field, a torque acting on the moments tends to align them along the field's direction. However, the random thermal motion of electrons produces a torque opposite to the external field and tries to disorient the moments. These two competing effects align only a few moments along the...
2.4K