Quadrannulene: A Nonclassical Fullerene Fragment
Quadrannulene: A Nonclassical Fullerene Fragment
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DOI：
10.1002/anie.200905633
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
King, Benjamin T.
中科院分区：
文献类型：
--
作者：
Kumar, Bharat;Bhola, Radha;King, Benjamin T.
非六边形环在石墨晶格中的存在会引起曲率。五边形很常见——十二个五边形被六边形包围，构成C60。在Stone-Wales缺陷中存在较大的环，而欧拉多面体公式要求它们存在于碳纳米管y结中然而，除了单个部分饱和的例子外，石墨结构中的[2]四元环是未知的。这些石墨结构中最小的例子是[n]环，其中中心的n面多边形被n-熔合苯环包围。Circulene最早是由山本、中崎及其同事于1983年制作的，呈马鞍状。环状环烯，或冕烯，是平凡的平面构型，由Scholl和Meyer于1932年首次合成，但也自然存在环状环烯（Circulene，或corannulene）占C60骨架的1/3，已被广泛研究，由Lawton和Barth于1971年首次制备虽然有一些开创性的尝试被报道，但[8][4]环烯从未被合成过。本文报道了稳定[4]环烯的制备和表征。与Lawton命名corannulene（拉丁语：cor，心；annula，环），[7]类似，我们建议将[4]环状母体命名为quadannulene（拉丁语：quadra，方形；annula，环）。因此，我们将这个衍生物命名为1,8,9,16 -tetrakis (trimethylsilyl) tetra-cata-tetraben-
The presence of nonhexagonal rings in an otherwise graphitic lattice induces curvature. Pentagons are common—twelve pentagons surrounded by hexagons make up C60. Larger rings are present in Stone–Wales defects, and the polyhedral formula of Euler mandates their existence in carbon nanotube Y-junctions.[1] Except for a single, partially saturated example,[2] four-membered rings in graphitic structures are, however, unknown. The smallest examples of these graphitic structures are the [n] circulenes, wherein a central n-sided polygon is surrounded by n-fused benzenoid rings.[3][7] Circulene, first prepared by Yamamoto, Nakazaki, and coworkers in 1983, is saddle shaped.[4][6] Circulene, or coronene, is the trivial, planar case, and it was first synthesized by Scholl and Meyer in 1932 [5] but also occurs naturally.[5] Circulene, or corannulene, comprises 1/3 of the C60 skeleton and has been intensely studied,[6] and it was first prepared by Lawton and Barth in 1971.[7] Whereas a few pioneering attempts have been reported,[8][4] circulene has never been synthesized before.We report herein the preparation and characterization of a stable [4] circulene. By analogy with Lawton s naming of corannulene (Latin: cor, heart; annula, ring),[7] we suggest the trivial name quadrannulene (Latin: quadra, square; annula, ring) for the [4] circulene parent. Hence, we name this derivative 1, 8, 9, 16-tetrakis (trimethylsilyl) tetra-cata-tetraben-