Aryl radical anions: key intermediates on the route to sustainable green-light ionizations

芳基自由基阴离子：可持续绿光电离途径的关键中间体

• 批准号: 275794373
• 负责人: Professor Dr. Martin Goez
• 金额: --
• 依托单位: Arbeitsbereich Organische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/275794373?language=en
• 关键词: Aryl; radical; anions; key; intermediates

Aqueous photoionizations produce hydrated electrons, which have already been successfully used for the reductive detoxification of halogenated organic waste and for the direct reduction of nitrogen or carbon dioxide; however, all these procedures had to rely on UV-C light (< 254 nm) for electron generation. Our proposal is concerned with photoionizations that require only green light (532 nm) and are based on catalytic cycles such that nothing but a bioavailable sacrificial donor is consumed.Starting from our very recently published exploratory investigations on the ruthenium-tris(bipyridyl) dication (the first example of a completely green-light driven cyclic photoionization, but with a very low quantum yield) and on the naphthalene radical anion (which exhibits the highest quantum yield known to date for the green-light ionization of an unstable intermediate, but cannot be generated with green light), we intend to fulfil that assignment by a combination of both approaches in a micellar environment. To that end, the ruthenium compound shall serve us as a light-harvesting compound and an arene with a larger number of rings, e.g., a pyrene derivative, as a redox catalyst. By an energy transfer from the green-light excited ruthenium complex followed by an electron transfer from the sacrificial donor ascorbate, we store the energy of the first photon in the aryl radical anion, which we then ionize with a second green photon, recovering the redox catalyst in that process. The function of the micelle is to ensure the desired order of the reaction sequence and to suppress side reactions, both through noncovalent interactions.We anticipate aryl radical anions to exhibit good photoionizability because their rigid molecular skeleton should decelerate the radiationless deactivation of their excited states, which competes with the electron ejection, and their high energy content results in a high excess energy of electron formation. Through intensity dependent measurements of the electron yields by two-pulse laser flash photolysis, together with lifetime measurements of the excited radical anions, we intend to study both effects quantitatively.As we expect, this project will allow us to procure completely green-light driven electron sources with as high an efficiency as possible on one hand, and on the other hand will provide important new insight into the factors that gouvern the quantum yields of photoionizations.

水光离子化产生水合电子，这些电子已经成功地用于还原卤代有机废物排毒，并直接减少氮或二氧化碳的直接还原；但是，所有这些程序都必须依靠UV-C光（<254 nm）来产生电子。 Our proposal is concerned with photoionizations that require only green light (532 nm) and are based on catalytic cycles such that nothing but a bioavailable sacrificial donor is consumed.Starting from our very recently published exploratory investigations on the ruthenium-tris(bipyridyl) dication (the first example of a completely green-light driven cyclic photoionization, but with a very low quantum yield) and on the naphthalene自由基阴离子（表现出最高的量子产率，该量子的最高量子因不稳定的中间体的绿色电离已知，但不能用绿光产生），我们打算通过在胶束环境中两种方法的组合来实现这一分配。为此，钌化合物应将我们用作轻度收获的化合物，而芳烃具有较大的环，例如pyrene衍生物，作为氧化还原催化剂。通过从绿光激发唯一复合物中的能量转移，然后从牺牲供体抗坏血酸中转移电子转移，我们将第一光子的能量存储在芳基自由基阴离子中，然后我们将其用第二个绿色光子在该过程中恢复氧化还原催化剂。胶束的功能是通过非共价相互作用来确保反应序列的所需顺序和抑制侧反应。我们预期芳基自由基阴离子表现出良好的光电素化性，因为它们的刚性分子骨骼应减速其激发状态的无辐射式降低辐射状态，这会与他们的高能量成分相互竞争，并具有高度的能量，并且具有高度的能量。通过两种脉冲激光闪光光解对电子产率的测量，以及对激发自由基阴离子的终生测量，我们打算进行定量研究。正如我们所期望的那样，我们预期的是，该项目将使我们能够尽可能高地效率地效率地效率，并在其他手上和量子上提供量度，并提供重要的因素，并将其量的变量iNPERTION iNSENT iNSERVENT iNSUM INSUM INSEVENS提供给出。