Silver(I)-catalysed Synthesis of Cuneanes from Cubanes and their Investigation as Isosteres

银(I)催化古巴烷合成古巴烷及其等排体研究

• 批准号: 2284777
• 金额: --
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2284777
• 关键词: Silver; catalysed; Synthesis; Cuneanes; Cubanes

Using light to drive chemical reactions via photocatalysis has emerged as a powerful method in the effort to develop greener, more sustainable chemical synthesis. Decatungstate, a photoactive polyoxometalate (POM) compound, has shown great promise as a photocatalyst in organic chemistry as it avoids the use of precious metals common in similar catalysts and is able to mediate a variety of valuable C-H functionalisation reactions. It has also shown applicability in the late-stage functionalisation of complex molecules, which is an emerging strategy for enabling highly efficient derivatization of bioactive molecules.Despite the interest in and development of decatungstate-mediated H-atom transfer reactions in recent years, there are a number of drawbacks to its use. This photocatalyst is only active in ultraviolet light, which has practical limitations in organic synthesis, and C-H bond selectivities in complex molecules can be limited. These drawbacks need to be mitigated in order to further broaden the scope of this promising catalytic system. Despite the enormous diversity of POM compounds reported in the literature, decatungstate remains the only one in use as a C-H functionalisation photocatalyst in organic chemistry. There is therefore significant scope to further explore the application of POMs as photocatalysts in organic chemistry.Proposed solution and methodologyThe design and synthesis of various 'hybrid' polyoxometalate structures, which have organic ligands attached to the POM cluster, has been investigated extensively by the Newton group. These compounds have similar photochemical characteristics to decatungstate and may therefore be amenable to similar C-H activation chemistry, but with greater tunability due to organic modifications. These organic modifications may allow the energy levels of the POM cluster to be modified to allow for activity in visible light, or allow the addition of supramolecular binding elements that exert greater control over reaction selectivity. These possibilities will investigated in this PhD project.Previously, tuning of the metal cluster's HOMO / LUMO levels has been demonstrated using phosphonate linkages between the POM and organic ligand. This work will be expanded by designing and synthesizing a range of novel hybrid POM structures that will be fully characterised using a range of techniques including NMR, cyclic voltammetry and UV/Vis spectroscopy. The major goal of the project is to demonstrate the applicability and practicality of hybrid POMs as C-H activation catalysts, and the new catalysts will be therefore be tested in a range of photochemical reactions with the aim over overcoming some of the drawbacks of decatungstate. Alongside this, further novel chemistry using decatungstate will also be explored to expand the scope of this promising photocatalyst.

利用光通过光催化驱动化学反应已成为开发更绿色、更可持续的化学合成的有力方法。十钨酸盐是一种光活性多金属氧酸盐 (POM) 化合物，作为有机化学中的光催化剂显示出了巨大的前景，因为它避免了使用类似催化剂中常见的贵金属，并且能够介导各种有价值的 C-H 官能化反应。它还在复杂分子的后期功能化中显示出适用性，这是一种实现生物活性分子高效衍生化的新兴策略。尽管近年来十钨酸盐介导的氢原子转移反应引起了人们的兴趣并得到了发展，但其使用仍存在许多缺点。这种光催化剂仅在紫外光下具有活性，这在有机合成中具有实际局限性，并且复杂分子中的C-H键选择性会受到限制。需要减轻这些缺点，以进一步扩大这种有前途的催化系统的范围。尽管文献报道的 POM 化合物种类繁多，但十钨酸盐仍然是有机化学中唯一用作 C-H 官能化光催化剂的化合物。因此，进一步探索 POM 作为光催化剂在有机化学中的应用还有很大的空间。提出的解决方案和方法 Newton 小组已经广泛研究了各种“混合”多金属氧酸盐结构的设计和合成，这些结构在 POM 簇上附着有有机配体。这些化合物具有与十钨酸盐类似的光化学特性，因此可能适合类似的 C-H 活化化学，但由于有机修饰而具有更大的可调性。这些有机修饰可以允许修改 POM 簇的能级，以允许在可见光下活动，或者允许添加超分子结合元素，从而对反应选择性施加更大的控制。这些可能性将在这个博士项目中进行研究。 此前，已经使用 POM 和有机配体之间的膦酸酯键来证明金属簇的 HOMO / LUMO 水平的调节。这项工作将通过设计和合成一系列新型混合 POM 结构来扩展，这些结构将使用核磁共振、循环伏安法和紫外/可见光谱等一系列技术进行全面表征。该项目的主要目标是证明混合POM作为C-H活化催化剂的适用性和实用性，因此新催化剂将在一系列光化学反应中进行测试，旨在克服十钨酸盐的一些缺点。除此之外，还将探索使用十钨酸盐的进一步新颖化学，以扩大这种有前途的光催化剂的范围。