Shape-Selective Synthesis of Pentacene Macrocycles and the Effect of Geometry on Singlet Fission
Shape-Selective Synthesis of Pentacene Macrocycles and the Effect of Geometry on Singlet Fission
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DOI：
10.1021/jacs.0c09941
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发表时间：
2020-11-25
影响因子：
15
通讯作者：
Tilley, T. Don
中科院分区：
文献类型：
--
作者：
Bergman, Harrison M.;Kiel, Gavin R.;Tilley, T. Don
并五苯非凡的光物理和电子特性高度依赖于分子间的空间相互作用。发色团的大环排列已被证明可以对这些相互作用提供高水平的控制，但由于固有的合成挑战，并五苯的例子很少。在这项工作中，二茂锆介导的炔烃偶联被用作动态共价C-C键形成反应，以克级和四步或更少的步骤合成两种几何形状不同的含并五苯大环化合物。两个大环在溶液中发生单线态裂变，其速率相差一个数量级，而三线态重组的速率大致相同。这种单线态和三线态衰变率的独立调节对于高效单线态裂变材料的设计是非常理想的。二聚大环在固态下采用柱状堆积基序，晶格的并五苯单元之间具有大的空隙空间。
Pentacene's extraordinary photophysical and electronic properties are highly dependent on intermolecular through-space interactions. Macrocyclic arrangements of chromophores have been shown to provide a high level of control over these interactions, but few examples exist for pentacene due to inherent synthetic challenges. In this work, zirconocene-mediated alkyne coupling was used as a dynamic covalent C-C bond forming reaction to synthesize two geometrically distinct, pentacene-containing macrocycles on a gram scale and in four or fewer steps. Both macrocycles undergo singlet fission in solution with rates that differ by an order of magnitude, while the rate of triplet recombination is approximately the same. This independent modulation of singlet and triplet decay rates is highly desirable for the design of efficient singlet fission materials. The dimeric macrocycle adopts a columnar packing motif in the solid state with large void spaces between pentacene units of the crystal lattice.