Dibenzosilanorbornadienyl Cations and Their Fragmentation into Silyliumylidenes
Dibenzosilanorbornadienyl Cations and Their Fragmentation into Silyliumylidenes
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DOI：
10.1021/ja400306h
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发表时间：
2013-07-17
影响因子：
15
通讯作者：
Mueller, Thomas
中科院分区：
文献类型：
--
作者：
Gerdes, Claudia;Saak, Wolfgang;Mueller, Thomas
合成了三苯基取代的二苯并二硅氧烷二烯基阳离子11，并以其[B(C6F5)(4)]（-）盐的形式进行了分离。通过量子力学计算支持的核磁共振光谱和相应的乙腈盐的XRD分析对盐进行了表征。11[B(C6F5)(4)]在苯中热碎裂生成二苯基terphenylsilyborate 17[B(C6F5)(4)]。该工艺的高纯度中间体是溶剂络合的三苯基硅油- 8和氢取代和苯基取代的硅离子- 20。水飞蓟烯8与溶剂苯反应生成硅离子20，证明了这四种价电子在C-H键活化反应中的高电位。此外，苯中氢取代的硅离子20的不稳定性为硅基阳离子受挫路易斯对对二氢的活化以及强路易斯酸对二氢的活化开辟了新的机理视角。
The terphenyl-substituted dibenzosilanorbornadienyl cation 11 was synthesized and isolated in the form of its [B(C6F5)(4)](-) salt. The salt was characterized by NMR spectroscopy supported by quantum mechanical computations and by an XRD analysis of a corresponding acetonitrilium salt. The thermal fragmentation of 11[B(C6F5)(4)] in benzene results in the high-yield formation of diphenylterphenylsilylium borate 17[B(C6F5)(4)]. High-lying intermediates in this process are solvent-complexed terphenylsilyliumylidene 8 and the hydrogen- and phenyl-substituted silylium ion 20. The formation of silylium ion 20 by reaction of silyliumylidene 8 with the solvent benzene demonstrates the high potential of this four valence electron species in C-H bond activation reactions. In addition, the instability of the hydrogen-substituted silylium ion 20 in benzene opens new mechanistic perspectives particular for dihydrogen activation by silyl cationic frustrated Lewis pairs and in general for the dihydrogen activation by strong Lewis acids.