Long-Chain Linear Oligogermanes and Polygermanes with Tunable Optical and Electronic Properties: Steps Toward the Design of Tailored Molecular Electronics

通过这一奖项，化学系的化学合成计划资助俄克拉荷马州立大学的Charles S.Weinert教授合成含有锗原子链(低聚锗)的分子。众所周知，具有超长锗链和锗纳米材料的体系具有重要的电子和光学性质，这取决于链中锗原子的数量和链上附加的其他基团。在这项研究中，锗原子的数量和取代基团都得到了仔细的控制。由于这些分子的性质可以通过其组成的变化来调节，因此可以设计和制备具有特定吸收、发射和导电性质的离散分子。更广泛的影响包括开发具有可调光学性能的导电新材料，这些材料可用于透镜、探测器或其他光学应用。除了研究生的教育和培训，该项目还将涉及来自俄克拉何马州的美国原住民高中或本科生，最终目标是激励这些学生追求科学事业。Ge的单键链状化合物是一种令人感兴趣的Sigma离域效应，它导致了有趣的光学和电学性质，可以通过改变它们的组成来调节。最近的密度泛函计算表明，多锗，以及潜在的低锗，可以作为具有直接带隙的准一维半导体，其中价带和导带主要来自链状的锗骨架。在这个项目中，Weinert研究小组正在进行一系列不同的长链线性低聚锗的合成，以确定这些新分子是否会表现出类似于多锗类似物的有用的光学和/或导电属性。用核磁共振、紫外可见光谱、发射光谱、循环和差示脉冲伏安法、高分辨质谱学和X射线结晶学等技术对所制备的新分子进行了表征。研究这些分子的固态结构是很重要的，因为低聚锗的整体几何结构会影响其物理性质。该项目的另一个方面涉及在高端电池的石墨电极中加入寡锗，以提高这些系统的整体性能，这些研究正在与奥地利格拉茨技术大学的一个研究小组合作进行。正在研究这些低聚锗的光化学，目的是影响这些分子的光化学重排，使之成为纯合成路线无法获得的新物种。

With this award, the Chemical Synthesis Program of the Division of Chemistry is funding Professor Charles S. Weinert of Oklahoma State University to synthesize molecules that contain chains of germanium atoms (oligogermanes). Systems with very long germanium chains and germanium nanomaterials are known to have important electronic and optical properties that depend on the number of germanium atoms in the chain and on the other groups appended to the chain. In this study, both the number of germanium atoms and the substituent groups are carefully controlled. Since the properties of these molecules can be tuned by variation of their composition, discrete molecules with specific absorbance, emission, and conductive properties can be designed and prepared. The broader impacts include the development of conductive new materials with tunable optical properties that may be used in lenses, detectors, or other optical applications. In addition to the education and training of graduate students, the project will involve Native American high school or undergraduate students from Oklahoma with the ultimate goal of inspiring these students to pursue careers in science. Singly-bonded catenates of germanium are of interest sigma-delocalization that results in interesting optical and electronic properties that can be tuned by varying their composition. Recent DFT calculations indicate that polygermanes, and potentially oligogermanes, can function as quasi-one dimensional semiconductors with a direct bandgap, where the valence and conduction bands result mainly from the catenated germanium skeleton. In this project, the Weinert research team is undertaking the synthesis of a diverse array of long-chain linear oligogermanes in order to ascertain if these new molecules will exhibit useful optical and/or conductive attributes akin to the polygermane analogues. The new molecules prepared in these investigations are characterized by a variety of techniques, including NMR, UV/visible, emission spectroscopy, cyclic and differential pulse voltammetry, high-resolution mass spectrometry, and X-ray crystallography. Studying the solid-state structures of these molecules is important since the overall geometry of the oligogermane affects its physical properties. Another aspect of this project involves the incorporation of oligogermanes into the graphite electrodes of high-end batteries in order to improve the overall performance of these systems, and these studies are being done in collaboration with a research team at Technical University in Graz, Austria. The photochemistry of these oligogermanes is being investigated, with the goal of affecting photochemical rearrangements of these molecules to new species that are not available by purely synthetic routes.