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

基于氰化物配体的团簇和扩展阵列的结构、磁性和光谱性质的系统研究

• 批准号: 0610019
• 负责人: Kim Dunbar
• 金额: $ 42.9万
• 依托单位: Texas A&M Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0610019&HistoricalAwards=false
• 关键词: Systematic; Studies; Structural; Magnetic; Spectroscopic

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.

该无机、生物无机和有机金属化学项目奖项支持德克萨斯农工大学 Kim Dunbar 教授的研究，准备一系列氰化物簇和一维阵列，以深入了解它们对分子大小、形状和基态大小的影响自旋（S）值以及特定金属自旋中心的组合对高自旋分子特性的影响。该提案包含两个主要合成目标：（1）基于混合八面体和五配位或四面体几何形状的新型双金属氰化物和三金属氰化物簇，以及（2）具有两种类型的构建单元的磁链族：（ a) 具有取代不稳定卤化物配体或悬挂氰化物的方形、立方体或三角形双锥氰化物簇，以及 (b) 具有反式二膦的八面体金属前体配体。簇的合成涉及使用二齿、三齿或五齿封端配体将维度限制在分子水平，以产生在低温下表现出缓慢顺磁弛豫和磁滞的分子。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。和华盛顿特区低温磁化率和 microSQUID 测量，以及穆斯堡尔和高场、高频 EPR 光谱。此外，还将研究新化合物的电化学和光学性质，以探索混合价态和光致磁行为。自旋交叉现象也将成为焦点。这项研究与磁存储器件、磁双稳态器件以及小长度尺度下磁响应的控制等潜在应用相关。该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。 与国内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。建议在德克萨斯农工大学举办专门针对该领域新手的免费夏季研讨会。