Gas Phase Proton Affinity,Basicity,and pK_a Values for Nitrogen Containing Heterocyclic Aromatic Compounds

摘要

Bipyridine and its derivatives have been widely used as the ligands in transition metal complexes.The proton affinities of pyridine derivatives were calculated using an ab initio quantum mechanical method(B3LYP with various double zeta and triple zeta basis sets)in combination with the Poisson-Boltzmann continuum solvation model.Van der Waals radii of the atoms in the heterocyclic rings for the solvation energy calculation were set to values determined to reproduce the pK_a values of guanine and oxoguanine derivatives and that of chlorine was optimized to reproduce the experimental values of relating compounds.The pK_a values for the heterocyclic ring compounds were in agreement with the experimental values with a mean unsigned error of 0.45 pK_a units.