Octahedral Metal Clusters as Building Blocks, Active Sites and Markers in New Materials

无机化学、生物无机化学和金属有机化学项目的这一奖项支持西北大学化学系杜沃德·F·施莱弗博士在具有不稳定配体的第5族和第6族金属簇合物方面的工作。这项工作的总体目标是合成扩展固体和包含氧化还原和光氧化还原活性的早期d-嵌段金属团簇的大分子团簇。新的化合物将被合成，并用光化学和电化学方法进行表征，作为制备微孔和介孔固体的基础，以及用作电子显微镜的标记。这些化合物将作为前驱体：(1)具有潜在兴趣的成键、反应、电化学和光化学的混合簇合物；(2)含有这些金属的非典型配体的簇合物；(3)由具有小分子和氧化还原或光电化学活性的大小和形状选择性的簇簇组成的固体。我们将研究团簇与固体上的官能团相互作用的一些可能性。例如，二氧化硅支撑的钼簇合物将被作为小分子的光化学或光电化学转化的固体介质进行研究。重金属簇合物将被用作多碳物种上官能团的标记。此外，一些团簇，可以很容易地通过高分辨率电子显微镜成像，并通过电子纳米衍射和光谱分析，将被用来区分竞争的碳纳米管结构模型。钼、钨、铌和钽形成六个金属原子组成的八面体核心，围绕核心是缔合离子，如氯化物。在这个项目中，容易交换的离子将与这些团簇中的一些结合起来，这样它们就可以附着在新材料的表面上。然后，可以使用这些团簇的尺寸、光化学和电化学来确定它们所附着到的载体材料的形状，或者增加团簇和表面的化学性能。这些结果可能有助于对已知材料的表征或合成新材料。

This award in the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports work on Group 5 and 6 metal clusters with labile ligands by Dr. Duward F. Shriver, Department of Chemistry, Northwestern University. The overall goal of the work is to synthesize extended solids and large molecular clusters containing redox and photoredox active early d-block metal clusters. New compounds will be synthesized and characterized photochemically and electrochemically, and used as the basis for preparation of micro- and mesoporous solids and for markers in electron microscopy. These compounds will serve as precursors to: (1) mixed clusters with potentially interesting bonding, reactivity, electrochemistry and photochemistry; (2) clusters containing atypical ligands for these metals; and (3) solids consisting of clusters of clusters with size and shape selectivity for small molecules and redox or photoelectrochemical activity. A number of possibilities for interaction of clusters with functional groups on solids will be investigated. For example, silica-supported molybdenum clusters will be investigated as a solid medium for photochemical or photoelectrochemical transformations of small molecules. Heavy metal clusters will be employed as markers for functional groups on polycarbon species. Also, some clusters, which can be readily imaged by high resolution electron microscopy and analyzed by electron nanodiffraction and spectroscopy, will be utilized to differentiate between competing structural models for carbon nanotubes. Molybdenum, tungsten, niobium, and tantalum form "clusters" in which six metal atoms form an octahedral core around which are associated ions, such as chloride. In this project easily exchangeable ions will be associated with some of these clusters so that they can be attached to surfaces of novel materials. The size, photochemistry, and electrochemistry of these clusters can then be used to determine the shape of the support material t o which they are attached, or to increase the chemical capabilities of both the cluster and the surface. The results could be helpful in characterizing known materials or in synthesizing new materials.