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

这个无机、生物无机和有机金属化学项目的奖项支持西北大学化学系Duward F. Shriver博士对具有不稳定配体的第5族和第6族金属簇的研究。这项工作的总体目标是合成含有氧化还原和光氧化还原活性的早期d-嵌段金属团簇的扩展固体和大分子团簇。新的化合物将被合成并进行光化学和电化学表征，并作为制备微孔和介孔固体和电子显微镜标记的基础。这些化合物将作为前体：(1)具有潜在的有趣键合，反应性，电化学和光化学的混合簇；(2)含有这些金属的非典型配体的簇；(3)由簇簇组成的固体，对小分子具有大小和形状选择性，具有氧化还原或光电化学活性。将研究固体上团簇与官能团相互作用的一些可能性。例如，二氧化硅支撑的钼团簇将被研究作为小分子光化学或光电化学转化的固体介质。重金属团簇将被用作聚烯烃物种官能团的标记。此外，一些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，将用于区分碳纳米管的竞争结构模型。钼、钨、铌和钽形成“簇”，其中六个金属原子形成一个八面体核心，其周围是相关的离子，如氯化物。在这个项目中，容易交换的离子将与这些簇中的一些相关联，以便它们可以附着在新材料的表面。这些团簇的大小、光化学和电化学可以用来确定它们附着的支撑材料的形状，或者增加团簇和表面的化学能力。研究结果可用于表征已知材料或合成新材料。

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.