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本文研究了四氟乙烯五聚体(Ⅰ)的反应,并得到一系列具有端基烯氟的新化合物Ⅱ、Ⅲ、Ⅵ。由化合物Ⅱ、Ⅲ(E)、Ⅵ(E)的~(19)F核磁共振谱,可观察到其中CF_2部分为二个相等强度的共振吸收峰,而化合物Ⅰ的CF_2部分为一单峰。比较一系列化合物结构和~(19)F核磁共振谱及~(19)F核磁共振变温实验后,可以发现在四氟乙烯五聚体及其衍生物中,密集的全氟叔己基基团按一定方向排列,其中二个全氟乙基中的CF_2基团在化合物Ⅲ(E)或Ⅵ(E)中与烯基氟在空间距离上是处于相近的,面对着的位置,而另一个CF_3基团则处于远离的背对着烯基氟的位置。在这里,二个CF_2基团产生磁不等性,从而导致不同的化学位移,这似乎是与相隔五个键的烯基氟的相互作用有关。
In this paper, we studied the reaction of pentafluoroethene (Ⅰ) and obtained a series of new compounds Ⅱ, Ⅲ and Ⅵ with terminal enketene. The ~ (19) F nuclear magnetic resonance spectrum of compounds Ⅱ, Ⅲ (E) and VI (E) shows that there are two identical resonance peaks in CF_2 and the CF_2 of compound Ⅰ is a single peak. Comparing a series of compound structures with ~ (19) F nuclear magnetic resonance spectra and ~ (19) F nuclear magnetic resonance temperature-changing experiments, it was found that the dense perfluoro-tert-hexyl groups in tetrafluoroethylene pentamers and their derivatives In which the CF 2 groups in the two perfluoroethyl groups are close to and confronted with the alkenyl fluoride in the compound III (E) or VI (E) while the other The CF 3 group is then far away from the alkenyl fluoride. Here, two CF 2 groups generate magnetic inequalities, leading to different chemical shifts, which seems to be related to the interaction of alkenyl fluorides at five bonds.