The kinetic method reveals secondary deuterium isotope effects on the proton affinity and gas-phase basicity of glycine and alanine methyl esters Int. J. Mass Spectrom
Date
10/14/2003Abstract
The kineticmethod for measuring protonaffinities (PA) and gas-phasebasicities (GB) was applied to the methylesters of simple amino acids. The experiments show that the GB and PA values for deuterium labeled glycinemethylester are indeed greater than that of the corresponding unlabelled glycinemethylester. The PA of l-Ala-OCD3 is also slightly greater than that of the unlabeled alaninemethylester. The secondaryisotopeeffects originate, as shown by density functional theory, in differences in zero-point energies and thermal-energy corrections between H and D-bearing molecules.
