Quantum-chemical calculations of NMR chemical shifts of organic molecules: XII. Calculation of the 13C NMR chemical shifts of fluoromethanes at the DFT level

Abstract

Calculation was carried out of chemical shifts in 13C NMR spectra for a series of fluoromethanes CHnF4−n (n = 0–4) by the methods of the electron density functional theory GIAO-DFT taking in consideration the solvent effect in the framework of the polarizable continuum model Tomasi IEF-PCM. The best results were obtained at the use of Keal-Tozer KT3 functional combined with Pople standard basis sets 6-311G(d,p) and 6-311++G(d,p), and also with Jensen special set pcS-2 containing tight p-functions. The optimum reference in the calculation of chemical shifts in 13C NMR spectra for the fluoromethanes series is TMS.