Hydrogen Bonding Cavity Motifs about Metal Ions

描述（由申请人提供）：本提案中研究的目的是构建有关金属离子的微环境（次级配位球），以指导其化学反应。利用生物启发的方法，结合金属蛋白活性位点中发现的分子结构原理。已经开发了新的模块化多齿配体，其在配位不饱和金属离子周围产生刚性有机框架。这些配体将氢键（H-键）给予或接受基团定位在金属中心附近，形成特定的微环境。我们将研究氢键框架如何调节金属配合物的结构和反应性与终端氧配体和双（μ-氧）基序。这项工作的一个特殊方面是考虑的H-键的分子氧和C-H键的活化金属配合物。这项研究的长期目标包括发展金属辅助氧化催化的结构-功能关系。 金属蛋白质进行的化学反应尚未在合成系统中实现。这种化学多功能性至少部分来自蛋白质通过调节其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理解。这种类型的分析需要基本的反应性研究，其中可以如本文所述单独分析单个组分的影响。该提案中概述的系统可以控制定义金属离子周围结构的分子组分，从而允许开发其活性可以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对于构建关于反应性物种的微环境是有益的。这使得结构功能关系的系统研究，可以导致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.