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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.

本研究涉及大团簇分子的制备，主要是硼原子，但也包括碳原子和金属原子。硼簇化学主要由簇中只有12个原子的分子/二十面体/组成，已知的例子有数千个。相比之下，这样的13个原子的团簇可能不到200个，只有少数14个原子的团簇，直到最近，没有15个原子的团簇，也没有更大的团簇。这是不幸的，因为如果可以制备更大的化合物，则这种簇的几种实际和潜在应用，包括它们在催化和肿瘤治疗中的用途，将得到增强，制备这些大的超二十面体硼簇的最大障碍是，一旦你超过二十面体，簇中的原子必须与它们的原子形成更多的键。邻居比他们能舒服地做。然而，以前的理论工作表明，这可能只对13，14和15个顶点的化合物是一个问题，对于那些有16个或更多顶点的簇，可以采用避免这个问题的形状。这项工作的主要目标之一是尝试达到16个顶点及以上（我们目前离这个只有一个顶点），看看实际上会发生什么。我们制造超二十面体分子的方法是通过一种称为多面体膨胀的技术，这是一个两步的过程，首先通过添加2个电子打开簇，然后添加额外的原子以隐藏笼。尽管硼在超二十面体团簇中形成许多键是不舒服的，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这样的化合物，因为金属比硼大得多。因此，我们计划的策略之一是故意使用过渡金属顶点来更多地了解这些不寻常的分子，并帮助我们发现最终用硼制造相同化合物的方法。一个折中的办法是使用主族金属，它们的特性介于硼和过渡金属之间，我们也建议在这方面进行研究，计划的工作主要是制备新的簇并确定它们的结构。但除此之外，我们还计划通过计算研究这一领域的各个方面，最终希望能够建立一套工作规则，既帮助我们回顾性地理解实验结果，又帮助我们建立指导未来实验工作的有用协议。