Pairing fullerenes and porphyrins: supramolecular wires that exhibit charge transfer activity.
Pairing fullerenes and porphyrins: supramolecular wires that exhibit charge transfer activity.
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DOI：
10.1021/ja101937w
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发表时间：
2010-07
影响因子：
15
通讯作者：
Florian Wessendorf;Bruno Grimm;D. Guldi;A. Hirsch
中科院分区：
文献类型：
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作者：
Florian Wessendorf;Bruno Grimm;D. Guldi;A. Hirsch
阐述了将电子供体和电子受体配对的概念，这些电子供体和电子受体具有一个共同的特征，即线状特征，作为实现新型和多功能电子供体-受体纳米杂化的有力手段。重要的变量是微调(I)络合强度，(Ii)电子/能量转移行为，和(Iii)所得体系的溶解度。特别是，通过哈密尔顿受体/三聚氰酸基序的氢键组装的一系列超分子卟啉/富勒烯杂化化合物已经实现。将上述变量付诸实施，从(1)H核磁共振和稳态荧光分析中测定的缔合常数(K(ASS))被成功地调整为10(4)-10(5)M(-1)的范围。事实上，我们的详细研究证实，后者揭示了间隔基团的性质，即对亚苯基乙炔、对亚苯基乙烯、对亚乙炔和荧烯的性质以及间隔基的长度。互补进行的瞬时吸收研究证实，电子转移确实是我们这类新型电子供体-受体纳米杂化材料的工作方式，而能量转移如果有的话，只起到很小的作用。相应地形成的电子转移产物，即一电子氧化的卟啉和一电子还原的富勒烯，寿命很长，寿命可以达到几十纳秒的时间域。最后，我们利用电子转移、电荷分离和电荷复合的距离依赖关系，首次确定了氢键介导的电子转移的贝塔值(0.11A(-1))。
A concept is elaborated of pairing electron donors and electron acceptors that share a common trait, wire-like features, as a powerful means to realize a new and versatile class of electron donor-acceptor nanohybrids. Important variables are fine-tuning (i) the complexation strength, (ii) the electron/energy transfer behavior, and (iii) the solubilities of the resulting architectures. In particular, a series of supramolecular porphyrin/fullerene hybrids assembled by the hydrogen bonding of Hamilton receptor/cyanuric acid motif has been realized. Putting the aforementioned variables into action, the association constants (K(ass)), as they were determined from (1)H NMR and steady-state fluorescence assays, were successfully tweaked with values in the range of 10(4)-10(5) M(-1). In fact, our detailed studies corroborate that the latter reveal a dependence on the nature of the spacer, that is, p-phenylene-ethynylene, p-phenylene-vinylene, p-ethynylene, and fluorene, as well as on the length of the spacer. Complementary performed transient absorption studies confirm that electron transfer is indeed the modus operandi in our novel class of electron donor-acceptor nanohybrids, while energy transfer plays, if any, only a minor role. The accordingly formed electron transfer products, that is, one-electron oxidized porphyrins and one-electron reduced fullerenes, are long-lived with lifetimes that reach well into the time domain of tens of nanoseconds. Finally, we have used the distance dependence on electron transfer, charge separation and charge recombination, to determine for the first time a beta value (0.11 A(-1)) for hydrogen-bonding-mediated electron transfer.