科研之友
微信
新浪微博
Facebook
分享链接
摘要
The H-1 NMR chemical shifts of 12 ferrocenyl-triptycenes and -barrelenes, in conjunction with their X-ray crystallographically-determined structures, provide a picture of the diamagnetic anisotropic effect of the ferrocenyl moiety. It reveals that protons sited directly above a cyclopentadienyl ring are incrementally shielded by approximately 1.2 ppm, whereas those positioned adjacent to the iron atom are deshielded by approximately 1.5 ppm. These data allow an NMR-derived evaluation of the chi value for ferrocene as of -1660 x 10(-36) m(3)/molecule, about 25% higher than the currently accepted value for benzene. A particular feature of the present approach is that data are provided for individual protons in clearly defined geometric positions rather than for rotating methyl groups.
- 出版日期2014-2-1
