Solvent effect on 14N NMR shielding of glycine, serine, leucine, and threonine: comparison between chemical shifts and energy versus dielectric constant
The polarizable continuum model (PCM) is employed to describe the system in the condensed phase. The performance of DFT and PCM in describing high order nonlinear mixed electric and magnetic effects in condensed phase are described. In this paper we consider the effect of 10 solvents with a wide range of dielectric constants on 4 amino acids. NMR shielding values (ppm), isotropic and anisotropic effects, energy interaction between solute and solvent, and the effect of hydrogen bond on shielding are described. Direct and indirect solvent effects on shielding are also calculated. The observed solvent-induced shielding variation is more strongly related to the intensity of the solvent reaction field rather than on the change of molecular geometry induced by the solvent.
KEY WORDS: Solvent effect, 14N NMR shielding, Solvent-induced shielding, Polarizable continuum model, Amino acids
Bull. Chem. Soc. Ethiop. 2007, 21(1), 111-116.