Counterintuitive deshielding on the 13C NMR chemical shift for the trifluoromethyl anion

• Published in: Magnetic resonance in chemistry Vol. 58; no. 6; pp. 540 - 547
• Main Authors: Viesser, Renan V., Tormena, Cláudio F.
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 01.06.2020
• Subjects: 13C; Anions; carbanion; Carbon; Chemical equilibrium; chemical shift; Density functional theory; DFT; Electron density; Fluorine; Molecular orbitals; NMR; Nuclear magnetic resonance; Shielding; Tensors

The trifluoromethyl anion (CF3−) displays 13C NMR chemical shift (175.0 ppm) surprisingly larger than neutral (CHF3, 122.2 ppm) and cation (CF3+, 150.7 ppm) compounds. This unexpected deshielding effect for a carbanion is investigated by density functional theory calculations and decomposition analy...