• Title/Summary/Keyword: Poisson-Boltzmann continuum-solvation model

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Calculation of the Solvation Free Energy of the Proton in Methanol

  • Hwang, Sun-Gu;Chung, Doo-Soo
    • Bulletin of the Korean Chemical Society
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    • v.26 no.4
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    • pp.589-593
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    • 2005
  • The solvation free energy of proton in methanol was calculated by B3LYP flavor of density functional calculations in combination with the Poisson-Boltzmann continuum solvation model. In order to check the adequacy of the computation level, the free energies of clustering in the gas phase were compared with the experimental data. The solvents were taken into account in a hybrid manner, i.e. one to five molecules of methanol were explicitly considered while other solvent molecules were represented with an implicit solvation model.

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

  • Hwang, Sun-Gu;Jang, Yun-Hee;Chung, Doo-Soo
    • Bulletin of the Korean Chemical Society
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    • v.26 no.4
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    • pp.585-588
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    • 2005
  • 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.