Synthesis, Reactivity and Catalysis of New Metallacarborane complexes

碳硼烷、硼烷和金属碳硼烷具有有趣的结构，并且一直处于整个化学中对键合的新见解和基本理解的发展的最前沿。本项目主要研究新的早过渡/镧系元素和主族元素金属碳硼烷的合成和化学性质。该项目将在三个具体领域进行研究;在第一个研究中，我们希望开发主族碳硼烷衍生物，重点是反应性关系，旨在更好地了解这些不寻常化合物的化学性质。特别感兴趣的是新的第13/14主族元素配合物的化学，以及探索这些和相关的碳硼烷衍生物在催化中的潜在应用。第二类研究集中于合成新的高氧化态的金属碳硼烷型的早期过渡元素和镧系元素衍生物的努力，其与已知的亚氨基和环戊二烯络合物具有微妙的相似性。预期将合成的一些新材料具有可能包括期望的电子和/或光谱性质的感兴趣的物理性质，并且一些将是用于合成感兴趣的材料的有用前体。尽管这些系统中的许多已经被知道了一段时间，但是在金属酰胺、金属烷基化物和金属双金属化物的形成方面的这种化学的开发是惊人地不发达的。即使从已知的材料开始，我们也有机会开发出显着的复合物，其反应性从未被探索过，开发的时机已经成熟。图1示出了开发Ti（IV）体系的一种可能途径，该体系包含二羧酸配体和两个酰胺基（Ti（dicarbolide）}片段或杜鹃鸟配合物具有作为替代地球丰富的金属如Ca的潜力，并有望显示出与真实的配合物如Ca（HMDS）2和Ca类似的反应性（CH{SiMe 3}2）2，这两种化合物都显示出在一系列催化应用中的应用，包括但不限于聚硅氮烷合成、催化氢化胺化和催化硼氢化。然而，与裸露的Ca离子不同，金属二碳环化物片段可以通过增加二碳环化物配位面上的B和c取代基来进一步调节，使得可以掺入向系统提供电子密度的稳定基团。第三，作为我们研究的一部分，我们建议调查使用的dicarbollide配体支持的异金属系统。我们将形成双金属配合物，其中外金属将对这些配合物显示协同效应，从而改变它们的反应性并提高活性，并且正如Ae元素可以改变一样（第13族和Ln元素也是感兴趣的）第1族金属可以从Li变为Na，K，Rb等或非配位阳离子如PPN（Ph_3P =N= PPh_3），所研究的金属碳硼烷簇合物在催化、分子电子学等方面具有潜在的应用价值。该项目结合了一个非常强调的综合，新的复合体的特点，符合部门/大学和EPSRC的一些战略主题，使其成为一个优秀的项目，为培训学生。

Carboranes, boranes and metallacarboranes have interesting structures and have been at the forefront of the development in new insights and fundamental understanding of bonding throughout chemistry. This project is concerned with the synthesis and chemical properties of new early transition/lanthanide element and main group element metallacarboranes. This project will pursue studies in three specific areas; In the first of these studies we wish to develop main group carborane derivatives, with an emphasis on reactivity relationships aimed at a greater understanding of the chemistry of these unusual compounds. Of particular interest is the chemistry of novel group 13/14 main group element complexes, as well as exploration of potential applications of these and related carborane derivatives in catalysis. The second category of studies is focused on an effort to synthesize new high oxidation state early transition element and lanthanide element derivatives of the metallacarborane type, which bear subtle resemblance to known imido and cyclopentadienide complexes. Some of the new materials which will be synthesized are expected to have interesting physical properties possibly including desirable electronic and/or spectral properties, and some will be useful precursors for the synthesis of interesting materials. Despite many of these systems having been known for some time, exploitation of this chemistry wrt the formation of metal amides, metal alkyls and metal hydrides is amazingly underdeveloped. Even starting form known materials we have the opportunity to develop remarkable complexes the reactivity of which has never been explored and is ripe for development. Figure 1 shows one possible route to the development of a Ti(IV) system incorporating a dicarboloide ligand and two amide groups this {Ti(dicarbollide)} fragment, or Cuckoo complex, has the potential to act as a surrogate earth abundant metal such as Ca and hopefully displaying similar reactivitys to real complexes such as Ca(HMDS)2 and Ca(CH{SiMe3}2)2, both of which have shown application in a range of catalytic applications including, but not limited to, polysilazane synthesis, catalytic hydroamination, and catalytic hydroboration. Hoverer unlike a naked Ca ion the metal dicarbollide fragment can be further tuned by augmentation of the B and c substituents on the coordinating face of the dicarbollide, such that stabilising groups which provide electron density to the system may be incorporated. Thirdly, as part of our study we propose to investigate the use of heterometallic systems supported by the dicarbollide ligand. We will form bi-metallic complexes in which the exo-metal will display a synergistic effect on these complexes modifying their reactivity and enhancing activity, and just as the Ae element can be changed (group 13 & Ln elemental are also of interest) the group 1 metal can be changed from Li to Na, K, Rb etc. or non-coordinating cations such as PPN (Ph3P=N=PPh3).The metal carborane clusters studied in this research may have potential applications in catalysis, and molecular electronics. The project incorporates a strong emphasis on synthesis, characterization of new complexes which align to a number of the strategic themes of the department/university and EPSRC, making it an excellent project for training students.