Isolable silylene anion radical: Structural characteristics in the solid state and in solution
Isolable silylene anion radical: Structural characteristics in the solid state and in solution
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DOI：
10.1021/ja0711314
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发表时间：
2007-05-16
影响因子：
15
通讯作者：
Sekiguchi, Akira
中科院分区：
文献类型：
--
作者：
Inoue, Shigeyoshi;Ichinohe, Masaaki;Sekiguchi, Akira
四(二叔丁基甲基硅基)二硅烯(1)在四氢呋喃中与2.2当量的金属萘化物(M=Li，Na)反应。当反应混合物中加入冠醚时，生成了硅烯阴离子自由基(BuMe2Si)-Bu-t)(2)Si：(中心点-)M(冠醚)(2)(+))(2a：m=Li，2b：m=Na)。它们以锂盐或钠盐的形式被分离出来，成为对空气和湿度非常敏感的红色晶体。2的结构通过ESR波谱数据和X-射线晶体分析进行了明确的表征。2a的X-射线晶体结构显示为自由的亚甲基阴离子，不与反离子(溶剂分离离子对)相互作用。2在溶液中的结构也由ESR波谱确定。2a和2b在极性溶剂(四氢呋喃或二甲醚)中的ESR谱显示溶剂分离的离子对，而2b在甲苯中的ESR谱显示由于反离子与阴离子硅原子的相互作用而显示接触离子对。
Tetrakis(di-tert-butylmethylsilyl)disilene (1) was treated with 2.2 equiv of metal naphthalenide (M = Li, Na) in THF. When a crown ether was added to the reaction mixture, the silylene anion radical (((BuMe2Si)-Bu-t)(2)Si:(center dot-) M(crown ether)(2)(+)) (2a: M = Li, 2b: M = Na) was formed. They were isolated in the form of the lithium or sodium salts as extremely air- and moisture-sensitive red crystals. The structures of 2 were unambiguously characterized by ESR spectroscopic data as well as by X-ray crystallographic analysis. The X-ray crystal structure of 2a reveals free silylene anion radical, showing no interaction with counterion (solvent-separated ion pair). The structures of 2 in solution were also deduced by ESR spectroscopy. The ESR spectra of 2a and 2b in a polar solvent (THF or DME) show a solvent-separated ion pair, whereas the ESR spectrum of 2b in toluene shows contact ion pair owing to the interaction of the counterion with the anionic silicon atom.