Main Group and Transition Metal Complexes: From Fundamental Investigations to Photocatalysis

主族和过渡金属配合物：从基础研究到光催化

• 批准号: RGPIN-2014-04846
• 负责人: Richeson, Darrin
• 金额: $ 3.93万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=566780
• 关键词: Main; Group; Transition; Metal; Complexes

This proposal addresses fundamental and applied aspects of compound design and catalyst development. More specifically, the proposal presents three core research themes: an exploration of noncovalent bonding interactions to metal centers; strategies to control anisotropy of single metal ions in complexes; and enhancing the light harvesting ability of Re compounds with the target of improved photocatalytic reduction of CO2. The first theme is centered on the fundamental objective to design and assemble molecular scaffolds that display an unusually low degree of covalent bonding between a metal cation and an associated Lewis base. Such noncovalent interactions is an important across diverse fields of molecular, biological and polymer science. We are contributing to a completely unique aspect of noncovalent interactions to inorganic chemistry. Prior to our work, the fundamental questions on how to control metal ligand bonding were not explicitly appreciated. The impact of these important fundamental interactions in main group chemistry has recently been appreciated in the literature to which we contributors. Understanding how to control metal-ligand bonding provides insights into methods to influence the Lewis acidity of metal cations, which directs aspects of their chemistry, and challenges conventional bonding descriptions of metal-ligand interactions. Our strategy is based on selecting bonding groups with restricted geometric features that dictate the alignment of their bonding features. We further extend this work to include main group compounds that are able to activate a number of small molecules (e.g. CO2, carbonyls, alkynes and nitrile bonds). This reactivity will be an important step forward in the realization of main group catalyst development. The fundamental motivation of our second theme is to control and dictate the electronic anisotropy of transition metal and f-element ions. Through steric and electronic tuning we will engender changes in physical, chemical, and magnetic properties of complexes. One objective is to produce single-ion cobalt and iron complexes whose anisotropies will reveal themselves as individual molecular magnets (so-called “single-molecule magnets”). Our approach provides us the unique opportunity to address the prediction of magnetic anisotropy based and thus remove some of the serendipity that is normally used in the synthetic work on SMMs. We also anticipate that this will lead to design of molecular magnetic building blocks. The control of geometric and electronic structure applied to catalysis are the concepts behind our third core theme which provides a major change to the photochemical and photophysical properties and applications of Re(I) complexes. While these features have been recognized since for some time and are noteworthy for the exceptional ability of these compounds to photocatalytically reduce CO2, the development of this field has been restricted by the limited structural and electronic variability of the common pseudo-octahedral fac-[ReX(CO)3L2] compounds. We will addresses these constraints by developing a new compounds that possess new coordination geometries for the Re centers. This new structure significantly elaboration of the basic photophysical features of this large class of compounds and should yield improved catalysts that would function with lower energy. Longer range objectives are targeting new approaches at Re(I) multimetallic networks. We also plan to expand this chemistry to novel porous materials that can function as heterogeneous CO2 ¬reduction catalysts as well as a means to study the changes to the fundamental changes to the photophysical features of the Re centers when arranged in ordered arrays.

该提案涉及化合物设计和催化剂开发的基础和应用方面。更具体地说，该提案提出了三个核心研究主题：探索与金属中心的非共价键相互作用；控制配合物中单一金属离子各向异性的策略；增强铼化合物的光捕获能力，以提高光催化还原二氧化碳的能力。第一个主题围绕设计和组装分子支架的基本目标，该分子支架在金属阳离子和相关路易斯碱之间表现出异常低的共价键合程度。这种非共价相互作用在分子、生物和聚合物科学的各个领域都很重要。我们正在为无机化学非共价相互作用的一个完全独特的方面做出贡献。在我们的工作之前，关于如何控制金属配体键合的基本问题并没有得到明确的认识。这些重要的基本相互作用对主族化学的影响最近在我们贡献的文献中得到了重视。了解如何控制金属-配体键合可以深入了解影响金属阳离子路易斯酸性的方法，从而指导其化学的各个方面，并对金属-配体相互作用的传统键合描述提出挑战。我们的策略是基于选择具有受限几何特征的键合基团，这些几何特征决定了其键合特征的对齐。我们进一步扩展这项工作，包括能够激活许多小分子（例如二氧化碳、羰基、炔烃和腈键）的主族化合物。该反应活性将是实现主族催化剂开发的重要一步。我们第二个主题的基本动机是控制和决定过渡金属和 f 元素离子的电子各向异性。通过空间和电子调谐，我们将引起配合物的物理、化学和磁性特性的变化。一个目标是生产单离子钴和铁络合物，其各向异性将表现为单个分子磁体（所谓的“单分子磁体”）。我们的方法为我们提供了独特的机会来解决基于磁各向异性的预测，从而消除 SMM 合成工作中通常使用的一些偶然性。我们还预计这将导致分子磁性构建块的设计。应用于催化的几何和电子结构控制是我们第三个核心主题背后的概念，它为 Re(I) 配合物的光化学和光物理性质及应用带来了重大变化。虽然这些特征已经被认可了一段时间，并且由于这些化合物光催化还原 CO2 的卓越能力而值得注意，但该领域的发展受到常见伪八面体 fac-[ReX(CO)3L2] 化合物有限的结构和电子可变性的限制。我们将通过开发具有新配位几何形状的 Re 中心的新化合物来解决这些限制。这种新结构极大地阐述了这一大类化合物的基本光物理特征，并且应该产生能够以较低能量发挥作用的改进催化剂。更长远的目标是针对 Re(I) 多金属网络的新方法。我们还计划将这种化学扩展到新型多孔材料，这些材料可以用作非均相二氧化碳还原催化剂，以及研究以有序阵列排列时 Re 中心光物理特征的基本变化的方法。