B19-: An Aromatic Wankel Motor
B19-: An Aromatic Wankel Motor
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DOI：
10.1002/anie.201001275
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Merino, Gabriel
中科院分区：
文献类型：
--
作者：
Jimenez-Halla, J. Oscar C.;Islas, Rafael;Merino, Gabriel
最近，Huang等人发现B19的最低能量形式À(1)是一个美丽的环状结构，两个平面π芳系相互嵌套内部碎片（环A）是一个共享2个π电子的六原子五边形基团，被13个硼原子（环B）的外围层包围，共享另外10个π电子（图1）。有趣的是，这两个片段都满足(4n+ 2) π h<s:1> ckel芳香性规则。一般来说，从B3到B20的中性和阴离子团簇的结构采用平面几何而不是三维团簇结构，大多数情况下是双芳族的特别是B8 2À， B9 À， B10, B11 À， B12和B13+硼簇可以被认为是苯的全硼类似物。[3-7]然而，B19 À是不同的，即使以前在有机化学中报道过同心π体系，也没有一个具有完全相同的电子构型。近十年来，人们从理论上提出了几种以主族元素[8-14]或过渡金属原子[15-18]为中心的硼轮。2005年，Erhardt等人研究了一些中心有一个以上碳的芳香硼轮（C2B8、c3b93 +和C5B11+）（图2）
Recently, Huang et al. found that the lowest energy form of B19 À (1) is a beautiful ring structure with two planar πaromatic systems nested inside one another.[1] The inner fragment (ring A) is a pentagonal six-atom group sharing two π electrons, surrounded by a peripheral layer of thirteen boron atoms (ring B), sharing further ten π electrons (Figure 1). Interestingly, both fragments individually satisfy the (4n+ 2) π Hückel aromaticity rule. In general, the structures of neutral and anionic clusters ranging from B3 to B20 adopt planar geometries rather than three-dimensional cluster structures, and in most cases are doubly aromatic.[2] Particularly, B8 2À, B9 À, B10, B11 À, B12, and B13+ boron clusters can be considered as all-boron analogues of benzene.[3–7] However, B19 À is different, even when concentric π systems have been reported in organic chemistry before, none has exactly this electronic configuration.In the last ten years, several boron wheels with maingroup elements [8–14] or transition-metal atoms [15–18] at the ring center have been proposed theoretically. In 2005, Erhardt et al. studied some aromatic boron wheels (C2B8, C3B9 3+, and C5B11+) with more than one carbon at the center (Figure 2).[19]