Exploratory Syntheses of Borometallic Molecular Wheels and Borospherenes

非技术总结：这项急切的提议旨在利用激光在液相中烧蚀的方法来合成固体形式的新型硼基纳米团簇的原理证明。如果概念验证的努力是成功的，那么使用湿化学的更好的合成路线可能会被发现来提高合成产率。这些新型的硼纳米结构的有效大规模合成方法的发展将代表着材料科学的重大进步。块状的硼纳米结构将提供具有潜在的电、磁和催化性能的新型材料。这个热切的项目还将为跨学科的本科生和研究生提供研究培训。技术综述：在过去的十年里，对尺寸选定的硼团簇的研究导致了从平面团簇到硼烯和硼球烯的各种有趣的纳米结构。近年来，在银衬底上合成了一类新型的二维材料--硼烯(或原子薄层)。这个热切的项目寻求探索固体形式的硼杂环烯(全硼笼状簇合物)的整体合成，以及过渡金属中心的硼环型簇合物M©Bn(n=8-10)，这是芳香的硼金属分子轮。由于硼的缺电子性质，硼金属簇合物和硼球烯的边缘或表面原子具有空的2p轨道，并有望与路易斯碱类型的配体反应，如酰胺或膦，这些配体将用于保护簇合物。在含有适当配体的溶液中，通过激光烧蚀适当的硼/金属复合材料或纯硼靶，将产生M©Bn型团簇和硼球烯。配体将配位到新生的硼纳米团簇上，以便分离它们，并随后进行结构和性质表征。激光烧蚀也可以在溶液之外进行，然后可以捕获新生的星团。合成方法将是物理和化学相结合的方法，而不像富勒烯合成方法是完全物理的方法(氦中的碳弧)。

Non-Technical Summary: This EAGER proposal is aimed at proof-of-principle syntheses of novel boron-based nanoclusters in solid forms using laser ablation in the liquid phase. If the prove-of-concept efforts are successful, better synthetic route using wet chemistry may be found to improve the synthetic yields. Development of effective large-scale synthetic methods of these novel boron nanostructures would represent significant advances in materials science. The boron nanostructures in bulk form will provide new classes of materials with potentially interesting electronic, magnetic, and catalytic properties. The EAGER project will also provide research training for undergraduate and graduate students across disciplines. Technical Summary: Studies on size-selected boron clusters over the past decade have led to a variety of interesting nanostructures from planar clusters to borophenes and borospherenes. Borophenes (or atomic thin boron layers) have recently been synthesized on silver substrates as a new class of 2D materials. This EAGER project seeks to explore bulk syntheses in solid forms of borospherenes (all-boron cage clusters), as well as transition metal centered boron ring type clusters, M©Bn (n = 8-10), which are aromatic borometallic molecular wheels. Due to the electron deficient nature of boron, the edge or surface atoms of the borometallic clusters and borospherenes have empty 2p orbitals and are expected to be reactive with Lewis base types of ligands, such as amides or phosphines, which will be used to protect the clusters. The M©Bn type clusters and borospherenes will be produced by laser ablation of appropriate boron/metal composite or pure boron targets in solutions, which contain the appropriate ligands. The ligands will coordinate to the nascent boron nanoclusters to allow their isolation and subsequent structural and property characterization. The laser ablation can also take place outside the solution, which can then capture the nascent clusters. The synthetic method will be a combination of physical and chemical approach, unlike the fullerene synthetic method, which is a completely physical method (carbon arc in He).