Kordts Natalie, Künzler Sandra, Rathjen Saskia, Sieling Thorben, Großekappenberg Henning, Schmidtmann Marc, Müller Thomas
Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Str. 9-11, 26211, Oldenburg, Germany.
Chemistry. 2017 Jul 26;23(42):10068-10079. doi: 10.1002/chem.201700995. Epub 2017 May 31.
The synthesis of two series of silylated chalconium borates, 9 and 10, which are based on the peri-naphthyl and peri-acenaphthyl framework, is reported (chalcogen (Ch): O, S, Se, Te). NMR investigations of the selenium- and tellurium-containing precursor silanes 3 d-f and 8 d, f revealed a significant through-space J-coupling between the chalcogen nuclei and the Me SiH group. Experimental and computational results typify the synthesized cations 9 and 10 as chalconium ions. The imposed ring strain weakens the Si-Ch linkage compared to acyclic chalconium ions. This attenuation of the Si-Ch bond strength is more pronounced in the acenaphthene series. Surprisingly, the Si-O bonds in oxonium ions 9 a and 10 a are the weakest Si-Ch linkage in both series. The synthesized silyl chalconium borates are active in hydrodefluorination reactions of alkyl fluorides with silanes. A cooperative activation of the silane by the Lewis acidic (silicon) and by the Lewis basic side (chalcogen) is suggested.
报道了基于萘并菲和苊并萘骨架的两个系列甲硅烷基化硼酸钅查化合物9和10的合成（硫属元素（Ch）：O、S、Se、Te）。对含硒和碲的前体硅烷3 d - f和8 d、f的核磁共振研究表明，硫属原子核与甲基硅氢基团之间存在显著的空间J耦合。实验和计算结果表明，合成的阳离子9和10为钅查离子。与无环钅查离子相比，所施加的环张力削弱了硅-硫属元素键。在苊系列中，硅-硫属元素键强度的这种减弱更为明显。令人惊讶的是，氧钅翁离子9 a和10 a中的硅-氧键是两个系列中最弱的硅-硫属元素键。合成的甲硅烷基硼酸钅查化合物在烷基氟化物与硅烷的加氢脱氟反应中具有活性。提出了通过路易斯酸性（硅）和路易斯碱性侧（硫属元素）对硅烷进行协同活化。
