Catalytic applications of transition metal-main group metal heterobimetallic complexes

该项目建立在Whittlesey集团最近的工作基础上，该工作导致了新的异双金属络合物的形成，这些络合物的特点是过渡金属(TM)和主族金属M‘，特别是锌之间的无支撑键。将富电子的后过渡金属中心与缺电子的M‘配对结合在一起的异双金属配合物有可能在催化反应中赋予两种截然不同的(潜在的互补)活性。文献中的催化活性TM-M‘系统主要特征是嵌入在配体支架中的缺乏电子的M’中心。然而，这降低了TM和M‘的配位不饱和度，并使得基本上不可能区分这些互补效应与(I)TM和M’在直接激活底物中的作用或(Ii)M‘间接作用于调节TM中心的性质。因此，我们的系统为这一化学研究领域提供了一种新的方法，因为Ru和Zn中心的配位不饱和导致了显著的化学计量和催化反应活性。我们现在将探索这些无载体的TM-M‘异双金属配合物在小分子的化学计量和催化活化方面的全部潜力。我们将致力于确定TM/M‘组合的限制，因为这对于在更广泛的意义上展示我们的无支持债券方法的可行性至关重要。这将涉及(I)M‘及其上的取代基，(Ii)Tm上的支持配体(例如，N-杂环卡宾(NHCS)和膦(Pr3))，(Iii)Tm前体(例如，LnRu变为[Pt(NHC)2H]+，[Ir(NHC)2H2]+)的变化。这项实验工作将由与赫里奥特-瓦特大学的斯图尔特·麦格雷戈教授合作进行的计算支持，惠特尔西目前与他共同获得了EPSRC的拨款。对于博士生来说，该项目在性质上是发展空气敏感材料操纵技能、学习催化原理并接触现代光谱和表征技术(核磁共振光谱、X射线结晶学)的理想选择。此外，开发新的异双金属体系化学的目标领域也是一个世界性的研究兴趣的话题。因此，学生将接触到模型无机/有机金属化学领域的主要研究人员。这项研究的潜在应用是设计新型均相催化剂，其新颖性在于提高了活性或转化了TM或M‘单独无法获得的类型。实现这些目标中的任何一个都将定义这项研究的好处，以及它与EPSRC的催化和可持续发展目标的相关性。第二位主管迈克·希尔在S化学和P-块化学方面有专业知识，因此将能够协助实现M‘的适当选择。

The project builds upon recent work in the Whittlesey group that has led to the formation of new heterobimetallic complexes which feature unsupported bonds between a transition metal (TM) and a main group metal M', specifically zinc. Heterobimetallic complexes that combine an electron-rich late transition metal centre with an electron-deficient M' partner have the potential to confer two very different (potentially complementary) activities in catalytic reactions. Catalytically active TM-M' systems in the literature mainly feature the electron-deficient M' centre embedded in a ligand scaffold. However, this reduces the level of coordinative unsaturation at both TM and M' and makes it essentially impossible to differentiate these complementary effects from being (i) the action of both the TM and M' in directly activating a substrate or (ii) M' acting indirectly to tune the properties of the TM centre. Our systems therefore offer a new approach to this area of chemical research, as the coordinative unsaturation of the Ru and Zn centres results in remarkable stoichiometric and catalytic reactivity. We will now explore the full potential of these unsupported TM-M' heterobimetallic complexes in the stoichiometric and catalytic activation of small molecules. We will aim to establish the limits of the TM/M' combination, as this is vital for showing the viability of our unsupported bond methodology in a broader sense. This will involve variation of (i) both M' and the substituents on it, (ii) the supporting ligands on TM (e.g. N-heterocyclic carbenes (NHCs) and phosphines (PR3)), (iii) the TM precursor (e.g. change of LnRu to [Pt(NHC)2H]+, [Ir(NHC)2H2]+). The experimental work will be supported by calculations in collaboration with Professor Stuart Macgregor at Heriot-Watt University, with whom Whittlesey has a current joint EPSRC grant. The project is ideal in nature for a PhD student to develop skills in the manipulation of air-sensitive materials, learn the principles of catalysis and gain exposure to modern spectroscopic and characterisation techniques (NMR spectroscopy, X-ray crystallography). Moreover, the target area to develop novel chemistry of heterobimetallic systems is a topic of worldwide research interest. Thus, the student will receive exposure to leading researchers in model inorganic/organometallic chemistry. The potential applications of this research are in the design of novel homogeneous catalysts, whose novelty lies in improved activity or transformations of a type inaccessible to either TM or M' alone. Achievement of either of these aims would define the benefit of this research and it's relevance to EPSRC goals of catalysis and sustainability. The second supervisor, Mike Hill, has expertise in s- and p-block chemistry and therefore will be able to assist in achieving appropriate choices of M'.