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

该提案涉及化合物设计和催化剂开发的基本和应用方面。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合相互作用;控制复合物中单个金属离子各向异性的策略;以及提高Re化合物的光捕获能力，目标是改善CO2的光催化还原。 第一个主题是集中在设计和组装分子支架的基本目标，显示一个不寻常的低程度的共价键之间的金属阳离子和相关的刘易斯基地。这种非共价相互作用在分子、生物和聚合物科学的不同领域中是重要的。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没有得到明确的认识。这些重要的基本相互作用在主族化学中的影响最近在我们贡献者的文献中得到了赞赏。了解如何控制金属-配体键合提供了对影响金属阳离子的刘易斯酸性的方法的见解，这指导了它们的化学方面，并挑战了金属-配体相互作用的传统键合描述。我们的策略是基于选择键合组与限制的几何特征，决定他们的键合功能的对齐。我们进一步扩展了这项工作，包括能够激活许多小分子（例如CO2、羰基、炔和腈键）的主族化合物。这种反应性将是实现主族催化剂发展的重要一步。 我们第二个主题的基本动机是控制和支配过渡金属和f-元素离子的电子各向异性。通过空间和电子调谐，我们将产生的物理，化学和磁性质的变化的配合物。一个目标是生产单离子钴和铁络合物，其各向异性将显示为单独的分子磁体（所谓的"单分子磁体"）。我们的方法为我们提供了独特的机会，以解决基于磁各向异性的预测，从而消除了一些通常用于SMM合成工作的意外发现。我们还预计，这将导致分子磁性积木的设计。 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和应用带来了重大变化。虽然这些特征已经被认识了一段时间，并且值得注意的是这些化合物光催化还原CO2的卓越能力，但该领域的发展受到常见的假八面体fac-[ReX（CO）3L2]化合物的有限结构和电子可变性的限制。我们将通过开发具有Re中心的新配位几何结构的新化合物来解决这些限制。这种新的结构显著地阐述了这一大类化合物的基本化学物理特征，并且应该产生将以较低能量起作用的改进的催化剂。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CO2还原催化剂，以及研究Re中心在有序阵列中排列时的物理特性的根本变化的变化。

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.