[Me3Si][R-CB11F11]-Synthesis and Properties
[Me3Si][R-CB11F11]-Synthesis and Properties
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DOI：
10.1002/anie.200701136
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Lehmann, Christian W.
中科院分区：
文献类型：
--
作者：
Kueppers, Torsten;Bernhardt, Eduard;Lehmann, Christian W.
亲电阳离子的合成和稳定需要化学性质稳定的弱配位阴离子或相应的路易斯超酸。 R= H、烷基或 F 的闭碳硼烷 [RCB11F11]¿ 属于弱配位阴离子，可抵抗氟化物的夺取。 [1]早在 1967 年就报道了母簇的各种盐，[2, 3]，而它们的氟化衍生物直到 30 年后才获得。[4] [CH3CB11F11]¿ 阴离子非常惰性，能够稳定极其亲电的 [Al (CH3) 2]+ 阳离子。 [5]尽管该化合物是二甲基铝阳离子盐的第一个例子，但迄今为止尚未报道其光谱或结构数据。Me3SiX 类型的三甲基甲硅烷基化合物由于快速形成挥发性 Me3SiF 或 Me3SiCl，因此是 X 与氟化物或氯化物交换的方便试剂。因此，与弱配位阴离子结合的 Me3Si 基团的组合应该允许在凝聚相中接触到新的亲电阳离子。在此，我们描述了[Me3Si][RCB11F11](R= H (1), C2H5 (2))的合成和性质。标题化合物以多步顺序制备，最后一步涉及三苯甲基盐与Me3SiH [6]的反应，如方程式(1)所示。
The synthesis and stabilization of electrophilic cations requires chemically robust, weakly coordinating anions or the corresponding Lewis super acids. The closo-carboranes [RCB11F11]¿ with R= H, alkyl, or F, belong to the group of weakly coordinating anions that are resistant to fluoride abstraction.[1] Various salts of the parent clusters were reported as early as 1967,[2, 3] while their fluorinated derivatives were only accessible 30 years later.[4] The [CH3CB11F11]¿ anion is so inert that it is able to stabilize the extremely electrophilic [Al (CH3) 2]+ cation.[5] Although this compound was the first example of a salt of a dimethylaluminium cation, no spectroscopic or structural data for it have been reported to date.Trimethylsilyl compounds of the type Me3SiX are convenient reagents for the exchange of X against fluoride or chloride due to rapid formation of volatile Me3SiF or Me3SiCl. Thus, the combination of a Me3Si group bound to a weakly coordinating anion should allow access to novel electrophilic cations in the condensed phase. Herein, we describe the synthesis and properties of [Me3Si][RCB11F11](R= H (1), C2H5 (2)). The title compounds were prepared in a multistep sequence, the last step of which involves the reaction of the triphenylmethyl salts with Me3SiH [6] as shown in Equation (1).