Title | Accurate calculation of N1s and C1s core electron binding energies of substituted pyridines. Correlation with basicity and with Hammett substituent constants |
Publication Type | Journal Article |
Year of Publication | 2008 |
Authors | Takahata, Y, Wulfman, CE, Chong, DP |
Journal | Journal of Molecular Structure-Theochem |
Volume | 863 |
Pagination | 33-38 |
Date Published | Aug |
Type of Article | Article |
ISBN Number | 0166-1280 |
Keywords | acid dissociation, BENZENE-DERIVATIVES, CEBE shifts, DENSITY-FUNCTIONAL CALCULATION, DFT, Hammett substituent (sigma) constant, ionization processes, PARAMETERS, pyridines, SHIFTS, SIGMA CONSTANTS, SPECTROSCOPY |
Abstract | Substituent shifts of the energetics of four related ionization processes of pyridines and benzoic acids (Fig. I) were investigated. The first process is core-electron ionization of gas-phase pyridines (Fig. 1A), while the second concerns gas-phase acid-base reaction between a substituted pyridine and a Conjugated acid (Fig. 1B), and the third and fourth processes are the acid dissociation of substituted benzoic acids in aqueous solution (Fig. 1C and in vacuum (Fig. 1D), respectively. Core-electron binding energies for the first process Were Calculated using density-functional theory with the scheme Delta E-KS (PW86x-PW91c/TZP+C-ret)//HF/6-31G*. Average absolute deviation of calculated core electron binding energy shifts at N atom in Substituted pyridines from experiment was 0.08 eV. The shift at N coincides highly with that at a ring carbon atom. The four shifts corresponding to the four processes shown in Figs. 1A-D correlate strongly with one another. with numerical values fairly close to each other when expressed in unit of electron volts. (C) 2008 Elsevier B.V. All rights reserved. |
URL | <Go to ISI>://000258791400006 |
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