Publication: MNDO Parameters for the Prediction of 19F NMR Chemical Shifts in Biologically Relevant Compounds
August 23, 2008
Abstract: The semiempirical MNDO methodology for qualitative description NMR chemical
shifts has now been extended with the addition of NMR-specific parameters for
the fluorine atom. This approach can be employed using semiempirical (AM1/PM3)
geometries with good accuracy and can be executed at a fraction of the cost of
ab initio and DFT methods, providing an attractive option for the computational
studies of 19F NMR for much larger systems. The data set used in the
parametrization is large and diverse and specifically geared toward biologically
relevant compounds. The new parameters are applicable to fluorine atoms involved
in carbon−fluorine bonds. These parameters yield results comparable to NMR
calculations performed at the DFT (B3LYP) level using the 6−31++G(d,p) basis
set. The average R2 and rms error for this data set is 0.94 and 13.85 ppm,
respectively, compared to 0.96 and 10.45 ppm when DFT methods are used.
Authors: Duane E. Williams, Martin B. Peters, Bing Wang and Kenneth M. Merz, Jr.
Reference:J. Phys. Chem. A, 2008, 112 (37), pp 8829–8838. (see
link for full paper).