Systematic Studies of the Structural, Magnetic, and Spectroscopic Properties of Clusters and Extended Arrays Based on Cyanide Ligands

无机，生物无机和有机化学计划的这一奖项支持德克萨斯州A M大学Kim Dunbar教授的研究，以制备一系列氰化物簇和一维阵列，以深入了解分子大小和形状的影响以及基态自旋（S）值的大小以及特定金属自旋中心对高自旋分子性质的组合。该提案包括两个主要的合成目标：（1）基于混合八面体和五配位或四面体几何形状的新的双金属和三金属氰化物簇，以及（2）具有两种类型的构建单元的磁性链家族：（a）正方形，具有取代不稳定的卤化物配体或悬挂氰化物的立方体或三角形双锥氰化物簇合物和（B）具有反式-双膦配体。簇的合成涉及使用二齿、三齿或五齿封端配体以将维度限制在分子水平，以产生在低温下表现出具有滞后的缓慢顺磁弛豫的分子。第二个目标是设计具有强链内耦合和伊辛各向异性的磁链。 计划的实验包括合成，结构表征和物理性质测量，包括交流。和直流磁化率和微SQUID测量在低温下，以及穆斯堡尔和高场，高频EPR光谱。此外，新化合物的电化学和光学性质将被研究，以探索混合价态和光致磁性行为。自旋渡越现象也将是一个焦点，这项研究与潜在的应用有关，如磁存储器件，磁存储器件，以及在一般情况下，在小长度尺度下的磁响应控制。这项研究将为学生和博士后提供有价值的多学科培训，他们将接触到该项目的合成和物理方面。 与国家和国际磁学界的合作为学生提供了向该领域专家学习的机会。一个专门为该领域新手举办的免费夏季讲习班拟在得克萨斯A M大学举行。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports research by Professor Kim Dunbar at Texas A&M University to prepare series of cyanide clusters and 1-D arrays in order to provide insight into their influence of molecular size and shape and magnitude of ground state spin (S) values as well as the combination of specific metal spin centers on the properties of high spin molecules. This proposal encompasses two main synthetic goals: (1) new bi- and tri-metallic cyanide clusters based on mixed octahedral and five-coordinate or tetrahedral geometries, and (2) families of magnetic chains with the building units being of two types: (a) square, cube or trigonal bipyramid cyanide clusters with subsitutionally labile halide ligands or dangling cyanides and (b) octahedral metal precursors with trans-diphosphine ligands. The synthesis of clusters involves the use of bidentate, tridentate or pentadentate capping ligands to restrict the dimensionality to the molecular level in order to produce molecules that exhibit slow paramagnetic relaxation with hysteresis at low temperatures. The second goal is aimed at the design of magnetic chains with strong intra-chain coupling and Ising anisotropy. Planned experiments include synthesis, structural characterization and physical properties measurements including a.c. and d.c. susceptibility and microSQUID measurements at low temperatures, as well as Mossbauer and high-field, high frequency epr spectroscopy. In addition, the electrochemical and optical properties of new compounds will be investigated to explore mixed valency and photoinduced magnetic behavior. The phenomenon of spincrossover, will also be a focus.This research has relevance to potential applications such as magnetic storage devices, magnetically bistable devices and, in general, the control of magnetic responses at small length scales. The research will provide valuable multi-disciplinary training to students and postdocs who will be exposed to both the synthetic and physical aspects of the project. Collaborations with the national and international magnetism community provide opportunities for students to learn from experts in the field. A no-fee summer workshop geared specifically for novices in the field is proposed to be held at Texas A&M University.