Hydrogen Bonding Cavity Motifs about Metal Ions

描述(申请人提供)：本方案的研究目的是构建关于金属离子的微环境(次级配位球)，以指导其化学。利用了一种生物启发的方法，结合了在金属蛋白活性部位发现的分子结构的原理。新的模块化多齿配体已经被开发出来，它们在配位不饱和金属离子周围创建刚性有机骨架。这些配体将氢键(H键)捐赠或接受基团放置在金属中心附近，形成特定的微环境。我们将研究氢键框架如何调节末端氧代配体和双(MU-氧代)基序的金属络合物的结构和反应活性。这项工作的一个特殊方面是考虑了氧中的氢键和金属络合物对C-H键的激活。这项研究的长期目标包括发展金属辅助氧化催化中的结构-功能关系。 金属蛋白执行尚未在合成系统中实现的化学反应。这种化学多样性至少部分源于蛋白质通过调节微环境来调节其金属中心的反应性的能力。因此，金属蛋白的功能和功能障碍可以在其微环境变化的背景下被理解。这种类型的分析需要进行基本的反应性研究，其中可以如本文所述单独分析单个组分的影响。本提案中概述的系统可以控制定义金属离子(S)周围结构的分子成分，从而允许开发活性可根据特定功能定制的络合物。微调外部配体结合位点的分子设计的能力有利于构建关于活性物种的微环境。这使得对结构功能关系的系统研究可以导致对化学和生物过程的基本理解。

DESCRIPTION (provided by applicant): The aim of the research in this proposal is to construct microenvironments (secondary coordination spheres) about metal ions to direct their chemistry. A bio-inspired approach is utilized that incorporates principles of molecular architecture found in the active sites of metalloproteins. New modular multidentate ligands have been developed that create rigid organic frameworks around coordinatively unsaturated metal ions. These ligands position hydrogen bond (H-bond) donating or accepting groups proximal to metal centers, forming specific microenvironments. We will investigate how H-bond frameworks regulate the structural and reactivity of metal complexes with terminal oxo ligands and bis(mu-oxo) motifs. A special aspect of this work is consideration of H-bonds in dioxygen and C-H bond activation by metal complexes. Long term goals of this research include developing structure-function relationships in metal-assisted oxidative catalysis. Metalloproteins perform chemical reactions that have yet to be achieved in synthetic systems. This chemical versatility follows at least in part from the ability of the proteins to regulate the reactivity of their metal centers by adjustments of their microenvironment. Thus the function and dysfunction of metalloproteins can be understood in the context of changes in their microenvironments. This type of analysis necessitates basic reactivity studies in which the effects of single components can be analyzed individually as described herein. The systems outlined in this proposal can control the molecular components that define the structure around the metal ion(s), thus permitting the development of complexes whose activity can be tailored to a particular function. The ability to fine-tune the molecular design of the external ligand-binding site is beneficial for constructing microenvironments about reactive species. This allows for the systematic study of structure function relationships that can lead to a fundamental understanding of chemical and biological processes.