Alkali-Metal-Ion-Centered Sandwich Structures of 4-Bromophenyl[tris(pentafluorophenyl)]borates and Their Synthetic Utility
Alkali-Metal-Ion-Centered Sandwich Structures of 4-Bromophenyl[tris(pentafluorophenyl)]borates and Their Synthetic Utility
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4-溴苯基[三(五氟苯基)]硼酸盐的碱金属离子中心夹层结构及其合成用途
DOI：
10.1021/acs.organomet.0c00711
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发表时间：
2021
期刊：
影响因子：
2.8
通讯作者：
Tokitoh Norihiro
中科院分区：
文献类型：
--
作者：
Iwai Kento;Mizuhata Yoshiyuki;Tokitoh Norihiro
氟化四芳基硼酸盐（FTAB）被认为是反应性阳离子和自由基阳离子的最佳伴侣之一。此外，离子取代基的迷人作用最近引起了有机化学家的广泛关注。鉴于这些背景，我们新设计了碱金属4-溴苯基[三(五氟苯基)]硼酸盐1[M·L](M = Li，Na，K，Cs，MgBr；L =配位溶剂)作为合成单元，以探索作为两性离子化合物的活性阳离子。通过这项工作，X射线晶体学分析揭示了1[M·L]独特的以碱金属为中心的夹层结构。应当指出的是，这些是碱金属硼酸盐的夹层结构的第一个例子。它们的夹心结构是由 M-Fortho 配位和对亚苯基部分的阳离子-π 相互作用诱导的，从而构建了一个阳离子捕获袋。作为1[K·C6H6]的合成用途，我们证明了1的锂-溴交换反应提供了相应的双阴离子物种2，可以通过连续添加二苯甲酮将其转化为硼烷三苯基甲醇3[K·DME]（DME = 1,2-二甲氧基乙烷）。
Fluorinated tetraarylborates (FTABs) are known as one of the best partners of reactive cations and radical cations. In addition, fascinating effects of ionic substituents have recently gathered much attention from organic chemists. In view of these backgrounds, we newly designed alkali-metal 4-bromophenyl[tris(pentafluorophenyl)]borates1[M·L](M = Li, Na, K, Cs, MgBr; L = coordinating solvents) as synthetic units to explore reactive cations as zwitterionic compounds. Through this work, unique alkali-metal-centered sandwich structures of1[M·L] were revealed by X-ray crystallographic analysis. It should be noted that these are the first examples of the sandwich structure of alkali-metal borates. Their sandwich structures were induced by the M–Forthocoordination and the cation−π interaction of thep-phenylene moiety, which constructed a cation-capturing pocket. As a synthetic utility of1[K·C6H6], we have demonstrated that the lithium–bromine exchange reaction of1afforded the corresponding dianionic species2, which can be converted to boranuidyltriphenylmethanol3[K·DME] (DME = 1,2-dimethoxyethane) by the successive addition of benzophenone.