The distance dependence of electron transfer (ET) is commonly investigated in linear rigid rod‐like compounds, but studies of molecular wires with integrated corners imposing 90° angles are very rare. By using spirobifluorene as a key bridging element and by substituting it at different positions, two isomeric series of donor‐bridge‐acceptor compounds with either nearly linear or angled geometries were obtained. Photoinduced ET in both series is dominated by rapid through‐bond hole hopping across oligofluorene bridges over distances of up to 70 Å. Despite considerable conformational flexibility, direct through‐space and through‐solvent ET is negligible even in the angled series. The independence of the ET rate constant on the total number of fluorene units in the angled series is attributed to a rate‐limiting tunneling step through the spirobifluorene corner. This finding is relevant for multidimensional ET systems and grids in which individual molecular wires are interlinked at 90° angles.

中文翻译：

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分子角附近的电子转移

通常在线性刚性棒状化合物中研究电子转移（ET）的距离依赖性，但对带有集成角为90°角的分子线的研究非常少见。通过使用螺二芴作为关键的桥联元素，并将其替换在不同的位置，获得了两个异构体系列的供体-桥-受体化合物，它们的几何形状接近线性或成角度。在两个系列中，光诱导的ET都以跨低聚芴桥的快速键合通孔跃迁为主，距离高达70Å。尽管构象具有很大的灵活性，但即使在成角度的系列中，直接通过空间和通过溶剂的ET也可以忽略不计。ET速率常数对成角度序列中芴单元总数的独立性归因于通过螺二芴角的速率限制隧穿步骤。这一发现与多维ET系统和网格有关，其中单个分子线以90°角互连。