EAGER: Molecular Rare-Earth Clusters in Reduced Oxidation States

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该奖项提交给无机、生物无机和有机金属（IBO）项目，支持马里兰大学Bryan Eichhorn教授对含有稀土原子（即La、Y、Gd）的分子簇的制备进行基础研究，这些分子簇具有直接的共价键。由于迄今为止还没有已知的此类化合物的例子，并且这种化学的发展将代表无机和簇科学的重大突破，因此该奖项是通过早期概念探索性研究资助（EAGER）计划获得的。Eichhorn教授和他的团队采用了一种独特的还原金属卤化物合成装置（schnokel反应器）来制备稀土单卤化物和二卤化物的溶液。加入立体负担的酰胺和羧基配体，促进低核簇的形成，即La2和La4簇。在较高温度下控制歧化反应被用来产生更大的“类金属”团簇，具有高核度的La核。目标f块元素（即Gd， Nd）用于产生由f电子直接耦合产生的高磁性团簇。这种磁性纳米团簇提供了对稀土元素直接金属-金属键合性质的基本见解，可以直接应用于磁存储组件、磁显像剂和有机转化催化剂。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The award, as submitted to the Inorganic, Bioinorganic and Organometallic (IBO) program, supports work by Professor Bryan Eichhorn at the University of Maryland to carry out fundamental studies on the preparation of molecular clusters containing rare-earth atoms (i.e., La, Y, Gd) with direct, covalent metal-metal bonds. As there are no previous examples of such compounds known to date and the development of this chemistry will represent a major breakthrough in inorganic and cluster science, this award is made through the EArly-concept Grants for Exploratory Research (EAGER) Program. Professor Eichhorn and his group employ a unique, reduced metal halide synthesis device (the Schnockel reactor) to prepare solutions of the rare earth monohalides and dihalides. Sterically-encumbered amido and carboxylato ligands are incorporated to promote the formation of low-nuclearity clusters, i.e., La2 and La4 clusters. Controlled disproportionation reactions at higher temperatures are being used to generate larger "metalloid" clusters with high nuclearity La cores. The targeted f-block elements (i.e., Gd, Nd) are used to produce highly magnetic clusters resulting from direct coupling of f-electrons. Such magnetic nanoclusters provide fundamental insight into the nature of direct metal-metal bonding for rare-earth elements and could be directly applicable as magnetic storage components, magnetic imaging agents, and catalysts for organic transformations.