High-valent iron complexes with bispidine ligands: Analysis of spin states and reaction channels

高价金属氧络合物在生物系统、环境和具有工业重要性的过程中都具有重要意义。通过双吡啶配体，我们已经建立并深入研究了一个平台，使我们能够猝灭和研究光谱上重要的中间体，并改变重要的参数，如配位几何结构、自旋态和驱动力，即氧化还原电势。我们相信，这将使我们能够理解一个人如何在特定的反应通道之间切换，以及重要的性质(结构、自旋、驱动力、反应性)是如何相互关联的。该项目的一个重要部分是确定驱动力和反应性如何依赖于自旋状态。我们相信，我们可以制备出在室温下接近自旋交叉的铁基体系。然后我们将确定高自旋(S=2)和中自旋(S=1)态的氧化还原势和反应性。此外，我们还提出了使迄今未知的S=0态可达的系统。观察这种物种的氧化还原电位和反应活性将是非常有兴趣的。另一个重要但研究得不够深入的问题是氧基的碱性。在这种情况下，一个重要的物种是金属-氧代-水配合物的互变构体，即我们几年前提出的二羟基配合物FeIV(OH)22+，我们现在已经有了初步的UV-Vis-NIR光谱。我们项目的实验研究将与我们小组所做的量子化学研究相结合。这一组合将使我们能够彻底解释光谱性质以及热力学和反应性。

High-valent metal-oxo complexes are relevant in biological systems, in the environment and in processes of industrial importance. With bispidine ligands, we have established and thoroughly studied a platform that enables us to quench and study spectroscopically important intermediates and to vary important parameters such as the coordination geometry, the spin state and the driving force, i.e. the redox potential. We believe that this will enable us to understand how one can switch between specific reaction channels and how important properties (structure, spin, driving force, reactivity) are correlated to each other.An important part of the project is to determine how the driving force and the reactivity depend on the spin state. We believe that we can prepare ferryl systems which at room temperature are close to the spin crossover. We then will determine the redox potential and reactivity at the high-spin (S=2) and intermediate-spin (S=1) states. In addition, we propose systems which should get the so far unknown S=0 state accessible. It will be of great interest to see what redox potential and reactivity such a species has.Another important and not well enough studied point is the basicity of the oxo group. An important species in this context is the tautomer of the metal-oxo-aqua complex, i.e. the dihydroxo complex FeIV(OH)22+ that we have proposed a few years ago and from which we now have preliminary UV-vis-NIR spectra.The experimental studies of our project will be combined with quantum chemical studies done in our group. This combination will allow us to thoroughly interpret the spectroscopic properties as well as thermodynamics and reactivities.