化物单分子磁铁表现出依赖溶剂的可逆"开启"和"关闭"交换偏差行为
Dawid Pinkowicz1, Heather I Southerland2, Carolina Avendaño2
1Faculty of Chemistry, Jagiellonian University , Ingardena 3, 30-060 Kraków, Poland.
Journal of the American Chemical Society
|November 7, 2015
概括
含有和重过渡金属的新复杂盐具有可切换的单分子磁铁和交换偏差特性. 溶解显著增强了磁性,证明了重元素对改善磁放松的重要性.
科学领域:
- 协调化学
- 材料科学
- 磁性
背景情况:
- 单分子磁铁 (SMM) 对于开发先进的磁性材料至关重要.
- 了解金属离子和溶剂含量在SMM特性中的作用至关重要.
- 异性交换相互作用会影响复杂盐的磁性行为.
研究的目的:
- 合成和描述具有潜在SMM和交换偏差行为的新复杂盐.
- 研究介质甲醇含量对磁性特性的影响.
- 探索重过渡金属 (Os,Ru) 对SMM性能的影响.
主要方法:
- 新型复合盐的合成: (PPN) {[Mn{III}{Salphen}{MeOH}}2[M{III}{CN}6}·7MeOH (M=Fe,Ru,Os,Co) 和一个混合的Co/Os类似物.
- 磁性测量,包括SMM行为和交换偏差效应.
- 不弹性中子散射和THz电子磁共振光谱.
主要成果:
- 所有合成的化合物都表现出可切换的SMM和取决于甲醇含量的交换偏差行为.
- Mn2Os·7MeOH的溶解使能量屏障 (Ueff/kB) 从17.1 K增加到42.0 K,并打开了歇斯底里循环.
- 引入重过渡金属 (Os,Ru) 增强了SMM的特性,在Mn (III) 和Os (III) 离子之间发现了异性交换相互作用.
结论:
- 甲醇含量极大地影响了这些复杂盐的磁性.
- 重过渡金属对于改善SMM中磁化的缓慢放松至关重要.
- 在观察到的磁现象中,异位交换相互作用起着重要作用.
更多相关视频
11:44Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes
Published on: November 12, 2016
18.7K
14:43Microfluidic On-chip Capture-cycloaddition Reaction to Reversibly Immobilize Small Molecules or Multi-component Structures for Biosensor Applications
Published on: September 23, 2013
11.3K
相关概念视频
Colors and Magnetism
14.6K
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...
14.6K
Ferromagnetism
3.5K
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...
3.5K
Ion Exchange
1.5K
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or...
1.5K
Valence Bond Theory
11.7K
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...
11.7K
Chemical Shift: Internal References and Solvent Effects
1.6K
In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
1.6K
Diamagnetism
3.4K
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....
3.4K
