HYDROGEN BONDING CAVITY MOTIFS ABOUT METAL IONS

这项研究的目的是调节金属离子的微环境(二次配位球)，以指导它们的化学。该方法利用了已在金属蛋白活性部位发现的分子结构原理。新的模块化三脚架配体已经被开发出来，它在配位不饱和金属络合物中的空位结合部位周围产生空洞。这些配体可以在空腔内定位官能团，以创建关于金属离子的特定化学微环境。我们将研究空穴结构如何影响金属络合物的功能和物理性质。将特别强调研究氢键和空穴的大小对指导金属中心化学的影响。一旦这些含有空穴的金属络合物的结构和物理性质得到表征，它们将被用来研究非血红素金属蛋白如何调节氧结合和激活，以及在催化中利用高度氧化或自由基中间体。这项研究的长期目标包括发展金属辅助氧化仿生催化的结构-功能关系。本提案中概述的系统提供了一种设计具有氢键空穴的新型仿生金属络合物的方法。对定义空腔结构的分子组分的控制允许开发其活性可针对特定反应和底物类别进行定制的系统。通过改变大小和氢键基团来微调外部配体结合部位的分子设计的能力有利于调节活性物种的微环境。这使得对结构-功能关系的系统研究可以导致对金属生物化学过程的基本理解。

The aim of this proposed research is to regulate the microenvironments (secondary coordination spheres) about metal ions to direct their chemistry. The approach utilizes the principles of molecular architecture that have been found in the active sites of metalloproteins. New modular tripodal ligands have been developed that create cavities around vacant binding sites in coordinatively unsaturated metal complexes. These ligands can position functional groups within the cavities to create specific chemical microenvironments about metal ions. We will investigate how cavity structure influences the functional and physical properties of metal complexes. Particular emphasis will be placed on studying the effects of the hydrogen bonds and the size of the cavities in directing chemistry at metal centers. Once these cavity-containing metal complexes are characterized both structurally and physically, they will be used to address how non-heme metalloproteins regulate dioxygen binding and activation, and utilize highly oxidized or radical intermediates in catalysis. Long term goals of this research include developing structure-function relationships in metal-assisted oxidative biomimetic catalysis. The systems outlined in this proposal offer an approach to designing new biomimetic metal complexes that have H-bonding cavities. The control of the molecular components that define the cavity structure permits the development of systems whose activity can be tailored to a particular reaction and class of substrates. The ability to fine-tune the molecular design of the external ligand binding site by varying the size and H-bonding groups is beneficial for regulating the microenvironment about active species. This allows for the systematic study of structure-function relationships that can lead to a fundamental understanding of metallobiochemical processes.