Pushing the Boundaries of Supraicosahedral Heteroborane Chemistry: New Supraicosahedral Carboranes and Metallacarboranes

突破二十面体杂硼烷化学的界限：新的二十面体碳硼烷和金属碳硼烷

基本信息

批准号：
EP/E02971X/1
负责人：
Alan Welch
金额：
$ 64.41万
依托单位：
Heriot-Watt University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FE02971X%2F1
关键词：
Pushing Boundaries Supraicosahedral Heteroborane Chemistry

项目摘要

This research is concerned with the preparation of large cluster molecules, mainly of boron atoms but also carbon and metal atoms as well. Boron cluster chemistry is dominated by molecules with only 12 atoms in the cluster / the icosahedron / of which there are thousands of known examples. In contrast there are probably less than 200 such clusters with 13 atoms, only a handful with 14 atoms, and, until very recently, no such clusters with 15 atoms, and nothing larger. This is unfortunate as several of the actual and potential applications of such clusters, including their use in catalysis and in tumour therapy, would be enhanced if larger compounds could be made, particularly if more boron atoms could be incorporated.The biggest obstacle to the preparation of these large supraicosahedral boron clusters is that once you get beyond the icosahedron the atoms in the cluster have to make more bonds to their neighbours than they can comfortably do. However, previous theoretical work has suggested that this may only be an issue for 13, 14 and 15-vertex compounds, and that for those clusters with 16 or more vertices, shapes can be adopted which avoid this problem. One of the major aims of the proposed work is to try to get to 16 vertices and beyond (we are currently only one vertex away from this) to see what actually happens.The way we will make the supraicosahedral molecules is by a technique know as polyhedral expansion , a two step process in which we first open up the cluster by adding 2 electrons then add the additional atom to recluse the cage. Even though boron is uncomfortable in making many bonds in supraicosahedral clusters we can still prepare and study such compounds by adding transition metal atoms instead of boron, because metals are significantly larger than boron. Part of our intended strategy, then, is deliberately to use transition metal vertices to learn more about these unusual molecules, and to help us discover ways to ultimately make the same compounds with boron. A halfway-house would be to use main group metals, which have characteristics between those of boron and transition metals, and we also propose to research in this area.Most of the planned work is concerned with preparing new clusters and determining their structures. But in addition we are also planning to study aspects of this area computationally, with the ultimate hope of being able to establish a set of working rules, both to help us understand the experimental results retrospectively and to help us establish useful protocols that will guide future experimental work.

这项研究涉及大簇分子的制备，主要是硼原子，也包括碳和金属原子。硼团簇化学主要由团簇（二十面体）中只有 12 个原子的分子主导，其中有数千个已知的例子。相比之下，这样的 13 个原子的簇可能不到 200 个，只有少数有 14 个原子，而且直到最近，还没有这样的 15 个原子的簇，也没有更大的簇。这是不幸的，因为如果可以制造更大的化合物，特别是如果可以掺入更多的硼原子，那么这种团簇的一些实际和潜在应用，包括它们在催化和肿瘤治疗中的应用，将会得到增强。这些大型超二十面体硼团簇的一个特点是，一旦超出二十面体，团簇中的原子就必须与其邻居建立更多的键，而这超出了它们可以轻松做到的程度。然而，之前的理论工作表明，这可能仅是 13、14 和 15 顶点复合的问题，对于具有 16 或更多顶点的簇，可以采用避免此问题的形状。这项工作的主要目标之一是尝试达到 16 个顶点及以上（我们目前距离此只有一个顶点），以了解实际发生的情况。我们制造上二十面体分子的方法是通过一种称为多面体膨胀，这是一个两步过程，我们首先通过添加 2 个电子来打开簇，然后添加额外的原子来隐藏笼子。尽管硼不适合在超二十面体簇中形成许多键，但我们仍然可以通过添加过渡金属原子而不是硼来制备和研究此类化合物，因为金属明显比硼大。因此，我们预期策略的一部分是有意使用过渡金属顶点来了解更多有关这些不寻常分子的信息，并帮助我们找到最终用硼制造相同化合物的方法。中途的办法是使用主族金属，它们具有硼和过渡金属之间的特性，我们也建议在这个领域进行研究。大部分计划的工作涉及制备新的团簇并确定它们的结构。但除此之外，我们还计划对这一领域的各个方面进行计算研究，最终希望能够建立一套工作规则，既可以帮助我们回顾性地理解实验结果，也可以帮助我们建立有用的协议来指导未来实验工作。