The shielding effect of fluoroaromatic rings in NMR

详细信息    查看全文

• 作者：Toshinobu Korenaga ; Fuminao Kobayashi ; Kenji Nomura ; Takashi Sakai ; Kazuaki Shimada
• 关键词：DFT calculations ; Shielding effect ; Fluoroaromatics ; Quadrupole moment ; Phosphine
• 刊名：Journal of Fluorine Chemistry
• 出版年：December, 2013
• 年：2013
• 卷：156
• 期：Complete
• 页码：1-4
• 全文大小：967 K

文摘

The shielding effect of fluoroaromatics on nuclei was estimated using nucleus-independent chemical shift (NICS) calculations at the GIAO/B3LYP/6-311++G(2d,p) level. The strengths of diamagnetic contributions of hexafluorobenzene at more than 3.5 脜 above the ring center were estimated to be ca. 0.73 times those of benzene. The chemical shift of a proton located above the fluoroaromatic ring is shifted upfield owing to such a relatively weak shielding effect of fluoroaromatic; we demonstrated that in ¹H NMR measurement on BINAP bearing C₆F₅ groups.