Electronic structure-chemical property relationship of binuclear 3d-metal structures.

本课题旨在研究一种新型自适应二硫酯配体的镍铁配位化合物的电子结构与化学性质之间的关系。硫和晚期过渡金属之间的化学键具有各种有趣的性质，其中之一是相对较高的共价键。较高的共价特征有利于金属-硫键上金属位的电子耦合，这解释了自然界中各种金属-硫结构的性质和功能。与天然结构不同，合成结构中金属位点之间的电子耦合通常非常强，基本上不可能发生变化。为了克服这一限制，本研究项目解决了允许以系统方式改变双金属金属-硫结构中电子耦合强度的参数。对镍的双金属结构的初步研究表明，衰减电子偶联强度是提高这些化合物氧化氢分裂性能的合适手段。同样的镍双金属化合物也为硫桥双金属结构的（非）组装机制的定量研究提供了高保真模型，这些结构在《自然》中非常突出。本研究项目的所有前期和未来工作都依赖于一种新型配体框架的性质，它结合了芳香π体系和噻吩基团的自适应和动态配位性质。这使得这些配体可以结合单个和多个金属原子，并灵活地适应金属氧化态的变化，这使得这些化合物显然适合于定量机制工作，这是本研究项目的目标。从长远来看，该研究项目旨在开发反应性3d金属结构，以有效的方式催化电键能和化学键能的相互转换。

This research project aims at studying the relation between the electronic structure and the chemical properties of coordination compounds of nickel and iron from a novel type of adaptive dithiolate ligands. The chemical bond between sulphur and a late transition metal features a variety of intriguing properties, one of which is a comparatively high covalent character. A higher covalent character is beneficial for electronic coupling of metal sites across metal-sulphur linkages, which explains the properties and function of a variety of metal-sulfur structures in Nature. Different from natural structures, the electronic coupling between metal sites in synthetic structures typically is very strong and its variation is essentially not possible. To overcome this limitation, this research project addresses parameters that allow for varying the strength of electronic coupling in bimetallic metal-sulphur structures in a systematic fashion. Preliminary work on bimetallic structures of nickel showed that attenuating electronic coupling strength provides suitable means to increase the performance of these compounds in oxidative hydrogen splitting. The same bimetallic compounds of nickel also provided high-fidelity models for quantitative studies of the mechanism of (dis)assembly of sulfur bridged bimetallic structures that feature so prominently in Nature. All precedent and future work of this research project relies on the properties of a novel type of ligand framework, which combines the adaptive and dynamic coordination properties of aromatic π-systems and thiophenol groups. This has allowed these ligands to bind a single and multiple metal atoms and adopt flexibly to changes in metal oxidation states, which renders these compounds clearly suitable for the quantitative mechanistic work that is the objective of this research project. On the long run, this research project aims for developing reactive 3d-metal structures that catalyze the interconversion of electrical and chemical bond energies in an efficient manner.