The Open Natural Products Journal

2012, 5 : 1-6
Published online 2012 May 28. DOI: 10.2174/1874848101205010001
Publisher ID: TONPJ-5-1

Correlation Between Experimental and DFT/GIAO Computed C NMR Chemical Shifts of Organic Compounds. Effects of Asymmetry

Eduardo J. Borkowski , Maria A. Alvarez , Fernando D. Suvire and Ricardo D. Enriz
IMIBIO-CONICET, UNSL, Chacabuco 915, 5700 San Luis, Argentina.

ABSTRACT

The experimental 13C chemical shifts of five different series of organic compounds are compared with pre-dicted 13C NMR chemical shifts obtained via empirically scaled GIAO shieldings. Our results indicate that the inclusion of a scaling factor allow to obtain an excellent correlation between δcalc and δexp. Although the inclusion of asymmetry im-proves this correlation, such enhancement was not observed for all the 54 tested compounds. We found δRMS, a parameter related with the structural feature of the whole molecule, which could indicate the benefits of including asymmetry in these calculations.

Keywords:

DFT/GIAO calculations, 13C chemical shifts, Chemical shifts anisotropy asymmetry.