用长链装饰的形交叉复合体在室温下的多稳定性
Daniel Rosario-Amorin1,2, Pierre Dechambenoit1,2, Ahmed Bentaleb1,2
1CNRS, CRPP, UPR 8641 , F-33600 Pessac, France.
Journal of the American Chemical Society
|November 29, 2017
概括
这项研究引入了一种罕见的旋转交叉化合物,具有长链,在室温和磁性度周围表现出广泛的热歇斯底里. 这种材料显示复杂的相位转换和独特的磁性行为.
科学领域:
- 材料科学
- 协调化学
- 磁力学
背景情况:
- 旋转交叉 (SCO) 化合物是可以在低旋转 (LS) 和高旋转 (HS) 状态之间切换的分子材料.
- 对于传感器,内存设备和显示器的应用,SCO材料很有意义.
- 在室温下实现广泛的热歇斯底里和多重磁性状态仍然是一个重大挑战.
研究的目的:
- 合成和表征一种具有长链的新型铁基酸复合物.
- 研究合成化合物的旋转交叉行为和热歇斯底里.
- 探索SCO材料中的磁性性和复杂相变的潜力.
主要方法:
- 一个具有长链的铁基酸复合物的合成.
- 测量可变温度的磁性易感性,以探测旋转转移和歇斯底里.
- 单晶X射线衍射以确定相变期间的晶体结构和对称性变化.
主要成果:
- 合成的复合物表现出一种罕见的旋转交叉行为,
- 在加热时,自旋转从LS基本状态转变为有序的HS-LS阶段,从单临床P21/n转变为正方形P212.
- 在冷却过程中,该化合物显示了两步过渡,首先是磁性明显的HS-LS阶段 (单临床P21),然后是LS阶段,显示了两个叠加的热歇斯底里循环.
- HS-LS阶段之间的相互转换是由链的结构变化驱动的,导致磁性稳定.
结论:
- 这种新型的铁II复合体在室温下表现出前所未有的磁性.
- 合作性旋转转移和联体驱动效应的结合使复杂的磁性行为成为可能.
- 这项工作为设计具有可调节磁性质的先进分子材料开辟了新的途径.
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