Synthesis and Structural Characterization of Pentaarylboroles and Their Dianions
Synthesis and Structural Characterization of Pentaarylboroles and Their Dianions
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DOI：
10.1021/om8002812
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发表时间：
2008-06
期刊：
影响因子：
2.8
通讯作者：
Cheuk-Wai So;D. Watanabe;A. Wakamiya;S. Yamaguchi
中科院分区：
文献类型：
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作者：
Cheuk-Wai So;D. Watanabe;A. Wakamiya;S. Yamaguchi
合成了一系列1-芳基-2，3，4，5-四苯基硼杂环戊二烯[Ph_4C_4BAr] [Ar = p-MeC_6 H_4（2），p-Me_3SiC_6 H_4（3），p-FC_6 H_4（4）]。2−4的X射线晶体学显示，它们的硼原子和相邻分子的苯环之间的距离很短，这表明存在一定的分子间相互作用。尽管存在这种相互作用，2−4中的硼杂环仍然保持平面，并在丁二烯骨架中包含大量的键交替，这与理论上优化的单重态硼杂环的结构一致。这些结果表明，硼杂环戊烯在结晶状态下仍具有反芳香性。化合物3和五苯基硼杂环戊烯[Ph 4C 4 BPh]（5）进一步与钾或钾石墨反应，分别形成硼杂环戊烯钾双阴离子盐[K2{Ph 4C 4 B（p-Me 3SiC 6 H4）}]（6）和[K2（Ph 4C 4 BPh）]（7）。化合物6和7的X-射线晶体结构表明，化合物6和7是聚合物，两个K+离子位于硼平面的两侧，η5-配位。
A series of l-aryl-2,3,4,5-tetraphenylboroles [Ph4C4BAr] [Ar = p-MeC6H4 (2), p-Me3SiC6H4 (3), p-FC6H4 (4)] were synthesized. The X-ray crystallography of 2−4 revealed that they have short distances between the borole boron atom and the phenyl rings of the neighboring molecules, suggesting the existence of certain intermolecular interaction. Despite this interaction, the borole rings in 2−4 remain planar and contain substantial bond alternation in the butadiene skeleton, which is consistent with the theoretically optimized structures of the singlet boroles. These results demonstrated that the boroles still have antiaromatic character in the crystalline state. Compound 3 and pentaphenylborole [Ph4C4BPh] (5) were further reacted with potassium or potassium graphite to form potassium borole dianion salts [K2{Ph4C4B(p-Me3SiC6H4)}] (6) and [K2(Ph4C4BPh)] (7), respectively. In their X-ray crystal structures, compounds 6 and 7 are polymeric and have two K+ ions lying on both sides of the borole plane with η5-coor...