Verification of a new concept for stabilizing radicals with elements of group 15 and studies concerning their use in one electron transfer reactions

在第一个资助期内，我们通过使用空间要求高的取代基（动力学稳定化）或通过强σ供体的配位（碱稳定化）以及通过在自由基中心引入正电性配体（电子稳定化），合成并结构表征了重族15元素（As，Sb，Bi）的几种均配和杂配自由基。除了中性自由基，我们还成功地在几乎未知的自由基阴离子的分离和结构表征。系统的研究揭示了第13族二酰化合物的还原电位的一般趋势以及氮族元素和离去基团R对反应的反应性/选择性的影响，而温度和时间依赖的NMR光谱研究提供了更深层次的反应机理理解。基于第一个资助期的发现，我们将在第二个资助期继续合成未知的自由基。重磷属元素的类型，即双硝烯自由基阳离子、没食子硝烯自由基阳离子和阴离子以及磷属烯自由基阳离子，并详细研究它们的电子性质。这些研究得到了我们的合作者Cutsail博士（EPR光谱学）和Haberhauer教授（DFT计算）的支持，以便对这些自由基的成键性质有一个基本的了解。此外，循环伏安法研究将提供对这些自由基的氧化还原行为的见解，而主族元素-氢（E-H）化合物的键活化反应将提供对这些自由基的化学势的见解。此外，我们将研究卤化物提取反应，这可能会提供额外的未知的中性和阳离子自由基。所有的研究都伴随着时间和温度依赖的NMR光谱研究以及量子化学计算，以提供基本的机理理解。

In the first funding period we have synthesized and structurally characterized several homoleptic and heteroleptic radicals of heavy group 15 elements (As, Sb, Bi) by using sterically demanding substituents (kinetic stabilisation) or by coordination of strong σ donors (base stabilisation) as well as by introducing electropositive ligands at the radical center (electronic stabilisation). Apart from neutral radicals we also succeeded in the isolation and structural characterization of virtually unknown radical anions. Systematic studies revealed general trends in the reduction potential of group 13 diyls as well as the influence of the pnictogen and the leaving group R on the reactivity / selectivity of the reactions, while temperature and time dependent NMR spectroscopic studies provided a deeper mechanistic understanding of the reactions.Based on the findings of the first funding period we will in the second funding period continue to synthesize unknown radical types of heavy pnictogenes, i.e. dipnictene radical cations, gallapnictene radical cations and anions as well as pnictinidene radical cations, and to study their electronic nature in detail. These studies are supported by our collaborateurs Dr. Cutsail (EPR spectroscopy) and Prof. Haberhauer (DFT calculations) in order to develop a fundamental understanding of the bonding nature in such radicals. In addition, cyclovoltammetric studies will provide insights into the redox behavior of such radicals, while bond activation reactions of main group element-hydrogen (E-H) compounds will provide insights into the chemical potential of such radicals. In addition, we will investigate halide abstraction reactions, which may provide access to additional unknown neutral and cationic radicals. All studies are flanked by time and temperature dependent NMR spectroscopic studies as well as quantum chemical calculations to provide a fundamental mechanistic understanding.