Continued search for elusive persistent trivalent organosilyl cations: the claimed trimethylsilyl cation revisited. Attempted preparation of cyclic and halogen-bridged organosilicenium ions
作者:George A. Olah、Golam Rasul、Ludger Heiliger、Joseph Bausch、G. K. Surya Prakash
DOI:10.1021/ja00046a020
日期:1992.9
Comparison of abinitio/IGLO calculated 1 H, 13 C, and 29 Si NMR chemical shifts with the experimental data on trimethylsilyl perchlorate and related derivatives supports the conclusions that no long-lived persistent trimethylsilicenium ion has been observed in solution. Attempts were made to prepare 5-methyl-5H-dibenzo[b,f]silepinium ion to probe whether cyclic aromatically stabilized silicenium could
ab initio/IGLO 计算的 1 H、13 C 和 29 Si NMR 化学位移与高氯酸三甲基甲硅烷基酯和相关衍生物的实验数据的比较支持以下结论:在溶液中没有观察到长寿命的持久性三甲基硅离子。尝试制备 5-甲基-5H-二苯并[b,f] 硅鎓离子,以探索是否可以在稳定的离子条件下制备环状芳香稳定的硅鎓。尝试没有成功,相关的高氯酸盐被发现是一种共价化合物。类似地,与声称电离的报道研究相反,还发现 1-甲基-和 1-苯基-取代的四苯基硅氧烷的杂交提取产物是共价高氯酸盐。silepium 和 silole 高氯酸盐在性质上都是共价的,分别没有芳香和反芳香特征的表现,表明 Si-O 键极化非常小。尝试制备硅烷取代的环状卤离子仅导致供体-受体复合物的形成和分解。在(溴甲基甲硅烷基)二苯基碳正离子的情况下,几乎没有溴桥连的迹象