Semiconducting Supramolecular Organic Frameworks Assembled from a Near-Infrared Fluorescent Macrocyclic Probe and Fullerenes
Semiconducting Supramolecular Organic Frameworks Assembled from a Near-Infrared Fluorescent Macrocyclic Probe and Fullerenes
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DOI：
10.1021/jacs.0c03699
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发表时间：
2020-07-01
影响因子：
15
通讯作者：
Jana, Atanu
中科院分区：
文献类型：
--
作者：
Kaur, Ramandeep;Sen, Sajal;Jana, Atanu
我们在这里报告了一种新的扩展四硫富瓦烯 (exTTF)-卟啉支架 2，它充当 C-60 和 C-70 的球窝受体。 2和这些富勒烯之间的超分子相互作用有助于稳定固态的3D超分子有机骨架（SOF），该骨架形式上包含豆荚状线性组装体。通过这种方式自组装制备的 SOF 充当“可调功能材料”，其中组件的互补几何形状和富勒烯的选择在定义电导特性方面发挥着至关重要的作用。在基于 C-70 的 SOF 中观察到最高的电导率（298 K 时 sigma = 1.3 x 10(-8) S cm(-1)）。相比之下，基于原始 2 的 SOF 电导率较低（298 K 时 sigma = 5.9 x 10(-11) S cm(-1)）。基于 C-70 的 SOF 的电导率与其他基于 TTF 和富勒烯的超分子材料的电导率接近，尽管目前的系统不含金属并且完全由中性构件构建。瞬态吸收光谱测量证实了溶液中电荷转移态的形成（即分别为 2(delta+)/C-60(delta-) 和 2(delta+)/C-70(delta-)），而不是完全电荷分离态（即分别为 2(center dot+)/C-60(center dot-) 和 2(center dot+)/ C-70(center dot-)） （甲苯和苯甲腈）并且在 298 K 下呈固态。这些发现被认为与在现有 SOF 内长距离有效转移电荷的能力一致，而不是例如形成能量捕获的离子物质。
We report here a new extended tetrathiafulvalene (exTTF)-porphyrin scaffold, 2, that acts as a ball-and-socket receptor for C-60 and C-70. Supramolecular interactions between 2 and these fullerenes serve to stabilize 3D supramolecular organic frameworks (SOFs) in the solid state formally comprising peapod-like linear assemblies. The SOFs prepared via self-assembly in this way act as "tunable functional materials", wherein the complementary geometry of the components and the choice of fullerene play crucial roles in defining the conductance properties. The highest electrical conductivity (sigma = 1.3 x 10(-8) S cm(-1) at 298 K) was observed in the case of the C-70-based SOF. In contrast, low conductivity was seen for the SOF based on pristine 2 (sigma = 5.9 x 10(-11) S cm(-1) at 298 K). The conductivity seen for the C-70-based SOF approaches that seen for other TTF- and fullerene-based supramolecular materials despite the fact that the present systems are metal-free and constructed entirely from neutral building blocks. Transient absorption spectroscopic measurements corroborated the formation of charge-transfer states (i.e., 2(delta+)/C-60(delta-) and 2(delta+)/ C-70(delta-), respectively) rather than fully charge separated states (i.e., 2(center dot+)/C-60(center dot-) and 2(center dot+)/ C-70(center dot-), respectively) both in solution (toluene and benzonitrile) and in the solid state at 298 K. Such findings are considered consistent with an ability to transfer charges effectively over long distances within the present SOFs, rather than, for example, the formation of energetically trapped ionic species.