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首页> 外文期刊>Chemistry: A European journal >Per-Substituted [8]Circulene and Its Non-Planar Fragments: Synthesis, Structural Analysis, and Properties
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Per-Substituted [8]Circulene and Its Non-Planar Fragments: Synthesis, Structural Analysis, and Properties

机译：取代的[8]环及其非平面片段：合成，结构分析和性质

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摘要

The syntheses, structures, and physical properties of a full series of benzannulated tetraphenylenes are reported. The palladium-catalyzed annulation of tetraiodo-substituted 2,3,6,7,10,11,14,15-octamethyltetraphenylene with insufficient di(4-anisyl)ethyne yielded a mixture of per-substituted [8]circulene and its non-planar fragments, including mono-, para-di-, ortho-di-, and triannulated products. Their structures were unambiguously verified by X-ray crystallography. Successive benzannulations significantly affect the molecular geometries, dynamic behaviors, and physical properties of the compounds. In this series of compounds, [8]circulene is the most strained one, as reflected by the significant deplanarization of the phenanthrene moieties (ca. 638 in the bay region) and the fact that it has the highest strain energy (120.6 kcal mol(-1)). The dynamic behaviors of these compounds were examined both experimentally and theoretically. The ring flipping of per-substituted [8]circulene is confirmed to proceed through pseudorotation with a barrier of around 21 kca mol(-1), whereas its non-planar fragments require much more energy for the ring inversion. The photo-physical and electrochemical properties of the investigated compounds depend strongly on the extent of efficient pi conjugation. The successive benzannulations red-shift both the absorption and the emission bands, and reduce the first oxidation potential.
机译：报道了全系列苯并二苯并四苯撑的合成，结构和物理性质。钯催化的四碘取代的2,3,6,7,10,11,14,15-八甲基四亚苯基与不足的二（4-茴香基）乙炔的环化反应生成全取代的[8]环及其非-平面碎片，包括单，对二，邻二和三环产品。 X射线晶体学明确地证实了它们的结构。连续的苯环化会显着影响化合物的分子几何形状，动力学行为和物理性质。在这一系列化合物中，[8]环烯是最应变的化合物，这反映了菲部分的显着去平面化（海湾区域约638个），并且它具有最高的应变能（120.6 kcal mol（ -1））。通过实验和理论研究了这些化合物的动力学行为。已证实，全取代的[8]环的环翻转会通过伪旋转进行，其势垒约为21 kca mol（-1），而其非平面碎片则需要更多的能量来进行环反转。所研究化合物的光物理和电化学性质在很大程度上取决于有效π共轭的程度。连续的苯环使吸收带和发射带都发生红移，并降低了第一氧化电位。

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