在三角 (III) 复合体中"开启"单分子磁性的特性
Theocharis C Stamatatos1, Dolos Foguet-Albiol, Sheng-Chiang Lee
1Department of Chemistry, University of Florida, Gainesville, FL 32611, USA.
Journal of the American Chemical Society
|July 12, 2007
概括
研究人员开发了新的三角形复合物,这些复合物表现出单分子磁铁行为. 这些集群由于其独特的结构和磁性特性,显示了先进磁性应用的潜力.
科学领域:
- 无机化学 无机化学 有机化学
- 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:
- 已知有氧化物中心的三角形化合物,含有碳酸盐连接体.
- 研究了将甲基2-基氧化物 (mpkoH) 作为连接体的结合.
- 了解连接体修饰的结构和磁性后果是关键.
研究的目的:
- 为了合成和表征一种新的Mn/carboxylato/oximato复合物的新家族.
- 为了研究三酸mpko-ligand引起的结构扭曲.
- 为了确定磁性特性,包括基态自旋和单分子磁铁行为.
主要方法:
- 合成 [MnIII3O(O2CR) 3(mpko) 3) ((ClO4) 复合物 (R = Me, Et, Ph). 这种复合物主要是由酸,酸和酸组成的.
- 进行X射线晶体学以确定分子结构.
- 测量直流磁化以确认基态旋转 (S=6).
- 交流敏感度测量以确定单分子磁铁 (SMM) 的特征.
- 磁化与时间衰变研究以及磁化与场扫描来分析磁化的量子道化 (QTM).
- 高频电子磁共振 (EPR) 光谱检测旋转哈密尔顿参数.
主要成果:
- 合成了新的三角形复合物[MnIII3O (((O2CR)) 3 ((mpko)) 3 ((ClO4).
- 三酸mpko-连接剂诱导三角形[MnIII3(mu3-O) ]7+核心的显著曲.
- 综合体表现出铁磁交换相互作用,导致S=6基本状态.
- 取决于频率的交流易感信号表明SMM行为.
- 观察到10.9K的有效放松屏障 (Ueff) 和地面状态QTM的证据.
- EPR光谱学提供了精确的自旋哈密尔顿参数,包括轴向和横向异性质.
结论:
- 合成的复合体代表了第一个三角形单分子磁铁 (SMM).
- 由外围连接体所造成的结构扭曲可以有效地"开启"SMM属性.
- 这些发现表明,设计具有可调磁特性的新型SMM的可行策略.
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