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

有了这个奖项，化学系的化学合成计划是资助教授查尔斯S。俄克拉荷马州州立大学的Weinert合成了含有锗原子链的分子（低聚锗烷）。已知具有非常长的锗链和锗纳米材料的系统具有重要的电子和光学性质，这些性质取决于链中锗原子的数量和附加到链上的其他基团。在本研究中，锗原子的数目和取代基都被仔细控制。 由于这些分子的性质可以通过改变其组成来调节，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特性的导电新材料，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外，该项目还将涉及来自俄克拉荷马州的美洲土著高中或本科生，最终目标是激励这些学生从事科学事业。锗的单键链是令人感兴趣的σ-离域，其导致可以通过改变其组成来调谐的有趣的光学和电子性质。 最近的DFT计算表明，多锗烷，和潜在的低聚锗烷，可以作为准一维半导体的直接带隙，其中的价带和导带主要是从链状锗骨架的结果。在这个项目中，Weinert研究小组正在合成各种各样的长链线性低聚锗烷，以确定这些新分子是否会表现出类似于多锗烷类似物的有用的光学和/或导电属性。在这些调查中制备的新分子的特征在于通过各种技术，包括NMR，UV/可见光，发射光谱，循环和差分脉冲伏安法，高分辨率质谱，和X射线晶体学。研究这些分子的固态结构是重要的，因为寡锗烷的整体几何形状影响其物理性质。 该项目的另一个方面涉及将低聚锗烷纳入高端电池的石墨电极中，以提高这些系统的整体性能，这些研究正在与奥地利格拉兹技术大学的一个研究小组合作进行。 这些低聚锗烷的光化学正在研究中，其目标是影响这些分子的光化学重排，使其成为纯合成途径无法获得的新物种。

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.