双核自旋交叉化合物的合成、穆斯堡尔谱和磁性研究

Synthesis,M?ssbauer Spectra and Magnetic Properties of a Dimeric Spin-crossover Complex

自旋交叉化合物的电子构型双稳性使其在分子传感器、信息存储器件等方面具有可观的应用前景.合成了一个在高温区发生自旋交叉转变的双核化合物并对其进行表征.173K的单晶结构解析显示该化合物的所有FeⅡ离子都处于低自旋态.FeⅡ离子通过与三氰基甲烷阴离子配体桥连,形成双核结构.常温穆斯堡尔谱显示该化合物含有2个独立的低自旋FeⅡ组分.变温磁化率测试表明,大约50%的该化合物分子在高温区(286~390K)发生从低自旋态到高自旋态的转变.该结果表明使用具有较强配体场的桥连配体可有效诱导自旋交叉行为.

Spin-crossover materials have attracted considerable interests due to their potential applications such as the deve-lopmentof miniature molecule-based display devices or data storage elements.We report here in the synthesis and characterization of a dimericFez complex that shows spin crossover at high temperatures.Single-crystal X-ray diffraction studies at 173 K revealed that the Fen i-ons were bridged by tricyanomethanide groups to form a dimeric structure,and the resulting complex was in a whole low-spin state.The Mossbauer spectrum at room temperature indicated that the complex was composed of two low-spin Fen species.Variable-tem-perature magnetic susceptibility measurements implied that about 50% of the complex molecules underwent a low-spin-to-high-spinconversion in the 286-390 K temperature range.The result indicates that spin crossover can be induced by strong bridging ligands.