Mechanistic Discovery for Materials Synthesis Across Scales using Atomically Precise Cluster Building Blocks

在化学系大分子、超分子和纳米化学项目的支持下，Brandi M。华盛顿大学的科萨伊特正在利用团簇前体开发新的纳米级材料。首先推导了新的和已知的团簇的结构和表面化学。接下来，通过调节化学环境来控制簇转化的机制，在簇之间移动作为溶质的来源，作为种子和作为离散的构建块。最后，网站分化是用来指导集群和集群组装，以访问新的中尺度结构，包括线，片，晶体。这一基础化学研究开辟了材料发现的新前沿，并为研究生和本科生提供了材料化学方面的培训机会。这种培训通过协调“纳米晶体西北”两年一度的研讨会得到加强，该研讨会汇集了来自R1和PUI机构以及工业界的太平洋西北地区的研究人员。此外，研究生在奖学金，指导和扩大参与的经验是通过华盛顿大学研究生口述历史项目记录。该项目还维持了化学妇女导师网络的进展，该网络在支持化学领域妇女的学术管道方面有着良好的记录，这项研究涉及使用原子精确的半导体簇作为前体合成和组装新型纳米材料。原子级精确的团簇的无机核心和表面化学结构被用来编码跨长度尺度的结构。此外，正在制定新的战略，调整集群转换和集群组装的机制。这包括使用单晶X射线衍射，对分布函数分析和透射电子显微镜相结合的新的和已知的半导体簇的结构，对称性和表面化学的阐明。簇转化机制的检查和控制使得随后能够选择簇作为溶质、种子和离散构建块。这通过在规定的反应条件下控制表面化学计量和配体密度来实现。最后，开发新的机制的网站分化正在追求形成所需的中尺度结构，包括线，片，和3D晶体从各向同性集群和crosslinked积木。这是通过使用空间控制调节双价来实现的。成功有望改变纳米材料合成的方法，并为材料发现打开一个巨大的未开发的参数空间。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

With the support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Dr. Brandi M. Cossairt of the University of Washington is developing new nanoscale materials using cluster precursors. The structure and surface chemistry of new and known clusters are first deduced. Next, the mechanisms of cluster transformation are controlled by modulating chemical environments, moving between clusters serving as sources of solute, as seeds, and as discrete building blocks. Finally, site differentiation is used to direct cluster and nanocrystal assembly to access new mesoscale structures including wires, sheets, and crystals. This fundamental chemistry research opens a new frontier in materials discovery and provides graduate and undergraduate student training opportunities in materials chemistry. This training is strengthened by coordination of the “Nanocrystals Northwest” biennial workshop, which brings together nanocrystal researchers in the Pacific Northwest from R1 and PUI institutions as well as industry. In addition, graduate student experiences in scholarship, mentorship, and broadening participation are documented through a University of Washington graduate student oral histories project. This project also sustains progress on the Chemistry Women Mentorship Network, which has a demonstrated track record in supporting the academic pipeline for women in chemistry.This research involves the synthesis and assembly of novel nanoscale materials using atomically precise semiconductor clusters as precursors. The inorganic core and surface chemical structure of atomically precise clusters are used to encode structure across length scales. In addition, new strategies to tune the mechanisms of cluster conversion and nanocrystal assembly are being developed. This includes elucidation of structure, symmetry, and surface chemistry of new and known semiconductor clusters using a combination of single crystal X-ray diffraction, pair distribution function analysis, and transmission electron microscopy. Examination and control of cluster transformation mechanisms enable the subsequent selection of clusters as solute, seeds, and discrete building blocks. This is accomplished by controlling surface stoichiometry and ligand density under prescribed reaction conditions. Finally, development of new mechanisms of site differentiation are being pursued for the formation of desired mesoscale structures including wires, sheets, and 3D crystals from isotropic cluster and nanocrystal building blocks. This is accomplished by adjusting nanocrystal valency using steric control. Success is expected to lead to change how nanomaterial synthesis is approached and to open a vast and untapped parameter space for materials discovery.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.