Oligomeric Metallocenes for Molecular Electronics

由多个共价键连接的茂金属单元组成的齐聚物是一类在分子电子器件中具有潜在应用前景的材料。该项目将专注于合成定制的茂金属低聚物，其特征在于线性方式中的两个或三个茂金属单元，或环状低聚物中的六个茂金属单元。特别强调的是将在一个彻底的和普遍的理解的方式，其中个别的氧化还原活性金属中心内的低聚物结构的通信，以及这种通信如何影响整体的电子和电化学性质，包括不同的氧化还原状态和自旋离域的程度的可访问性。因此，双茂金属和三茂金属以及六聚环的不同变体将通过改变中心金属来制备。化学氧化物质的分离将提供顺磁性的混合价化合物，其允许进入离域效应。然后将基于它们在分子水平上的性质来选择用于沉积为薄膜的合适的构建块。这种自下而上的方法将导致具有可预测性质（例如，无导电性或高导电性）的薄膜的定向制备。从材料科学家的角度来看，所得薄膜将通过多种技术（如AFM，SEM）进行表征，突出了该项目的跨学科方法。潜在的可转换特性，如导电性，将通过施加电压或氧化/还原条件得到的材料，使新的一类材料有望在分子电子器件中的应用，如分子开关，传感器和电线。

Oligomers consisting of multiple covalently linked metallocene units are a promising class of materials for potential application in molecular electronic devices. This project will focus in the synthesis of tailor-made metallocene oligomers featuring two or three metallocene units in a linear fashion, or six metallocene units in cyclic oligomers. Special emphasis will be on a thorough and generalized understanding of the ways in which the individual redox active metal centres within the oligomeric structure communicate and how this communication affects the overall electronic and electrochemical properties, including accessibility of distinct redox states and the degree of spin delocalization. Therefore, different variants of the bimetallocene and trimetallocene as well as of the hexameric ring will be prepared by varying the central metals. Isolation of chemically oxidized species will afford paramagnetic, mixed valent compounds, that allow for inisght into delocalization effects. Suitable building blocks for the deposition as thin films will then be chosen based on their properties on a molecular level. This bottom-up approach will lead to directed preparation of thin films with predictable properties (e.g. no or high conductivity). The resulting films will be characterized by a number of techniques (such as AFM, SEM) from a materials scientist´s point of view, highlighting the interdisciplinary approach of this project. Potentially switchable properties such as conductivity will be addressed by applying voltages or oxidating/ redcuing conditions to the resulting materials, making the new class of materials promising candidates for applications in molecular electronic devices, such as moleular switches, sensors, and wires.