三重基态双根的单点-三点差距是通过替代效应调节的
David A Shultz1, Scot H Bodnar, Hyoyoung Lee
1Department of Chemistry, North Carolina State University, Raleigh 27695-8204, USA. david_shultz@ncsu.edu
Journal of the American Chemical Society
|August 22, 2002
概括
合成了三种新的铁磁自旋合 bis ((semiquinone) 复合物. 结构分析显示了一致的连接体构造,替代效应主要影响观察到的交换合参数 (J).
科学领域:
- 无机化学 无机化学
- 材料科学 材料科学 材料科学
- 量子化学 是一个量子化学.
背景情况:
- 双 (半) 复合物因其独特的磁性特性而引起人们的兴趣.
- 内部分子交换合对于实现所需的磁性行为至关重要.
- 替代品的电子和硬质性能调节可以调节磁相互作用.
研究的目的:
- 为了合成和表征新型S = 1 bis ((semiquinone) 复合物.
- 为了研究元替代剂对铁磁内分子交换合的影响.
- 为了将结构形状与磁交换参数相关联.
主要方法:
- 合成了三种不同的双半) 复合体,含有不同的元替代物 (NMe2,t-Bu,NO2)).
- 进行X射线晶体学,以详细确定复合物的结构.
- 测量磁感应度以确定交换合参数 (J).
主要成果:
- 这三个复合体都表现出S = 1旋转状态与铁磁合.
- X射线晶体学证实了所有复合体中几乎相同的连接体构造 (半子环的平均扭矩为32°±2°).
- 交换合参数 (J) 从+31.0 cm−1 (NO(2) 变化到+59.3 cm−1 (t-Bu),表明取代剂依赖调制.
结论:
- 铁磁交换合的观察到的变化主要归因于电子替代效应,而不是形状变化.
- 这项研究提供了关于具有可调节磁性特性的分子磁铁的合理设计的见解.
- 赫克尔理论和计算工作支持对替代效应的实验发现.
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