Mimicking the active centres in iron-sulfur proteins: reaction kinetic study of the catalytic behavior and and the redox activity of free FexSy-clusters in an ion trap

小的铁硫（FeS-）簇通常被认为是最常见的天然蛋白质（FeS-蛋白）的活性中心，因此对所有生物都具有重要意义。除了在生化氧化还原反应中作为电子传递介质的功能外，fes簇在许多关键过程中作为生物催化剂尤其重要。特别是，温和的反应条件和这种生物催化剂激活空气成分的能力使它们成为“绿色”的理想材料，即环境友好和可持续的催化。因此，酶反应催化机制的研究不仅对生命功能的基本理解具有特别重要的意义；酶作为生物催化剂代表了从自然中学习的理想系统，并将这些知识用于工业上开发新的催化活性和选择性材料。然而，fes蛋白非常复杂的结构及其有机环境的影响极大地阻碍了对这一过程的详细了解。为了在分子水平上详细了解基本过程，必须分离蛋白质的活性中心并研究它们独立于环境的内在特性。在这种情况下，我们将以气相簇的形式模拟fes蛋白的活性中心，并将在离子阱实验中研究它们在不同模型反应中的氧化还原活性和催化性能。这种实验方法的目的是阐明基本反应步骤及其动力学，以及在严格的分子水平上理解涉及键激活和键形成过程以及相应的电荷转移过程的基本机制。特别强调的将是对有关燃料活化（用于燃料电池）、氢的演化、氨的合成以及脂肪族和芳烃的有效和选择性氧化的反应性的研究。对于这些系统，我们将进行反应动力学，反应动力学和结构确定实验，作为簇大小和簇组成的函数，以确定最活跃的簇。通过改变簇的电荷状态以及用Mo、V或Ni原子取代Fe原子，可以进一步优化簇的性质。

Small iron-sulfur (FeS-)clusters are often considered as the active centers of the most commonly naturally occurring proteins (FeS-proteins) and are thus of fundamental importance for all living organisms. Besides their function as electron transfer medium in biochemical redox reactions, FeS-clusters are especially important as biocatalysts in numerous pivotal processes. In particular, the mild reaction conditions and the ability of such biocatalysts to activate components of the air makes them ideal materials for a "green" i.e. environmentally friendly and sustainable catalysis. Thus, the investigation of the catalytic mechanisms in enzyme reactions is not only of particular importance for a basic understanding of the functionality of life; enzymes as biocatalysts rather represent ideal systems to learn from nature and to use this knowledge industrially for the development of new catalytically active and selective materials. The detailed understanding of the processes is, however, considerably hampered by the very complex structure of FeS-proteins and the influence of their organic environment. For a detailed understanding of the elementary processes on a molecular level it is mandatory to isolate the active centers of the proteins and to study their intrinsic properties independent of their environment. In this context, we will mimic the active centers of FeS-proteins in form of gasphase clusters and will study their redox activity and catalytic properties in different model reactions in an ion trap experiment. The aim of this experimental approach is the elucidation of elementary reaction steps and their dynamics as well as the understanding of basic mechanisms involved in bond activation and bond formation processes and the corresponding charge transfer processes on a strictly molecular level.Particular emphasis will be on the investigation of the reactivity with respect to the activation of fuels (for application in fuel cells), the hydrogen evolution, the ammonia synthesis as well as the effective and selective oxidation of aliphatic and aromatic hydrocarbons. For these systems we will perform reaction kinetic, reaction dynamic and structure determination experiments as a function of cluster size, and cluster composition to identify the most active clusters. Further optimization of the cluster properties will be achieved by changing the charge state of the clusters as well as by substitution of Fe atoms with Mo, V, or Ni atoms.