@article {2278, title = {Accurate calculation of N1s and C1s core electron binding energies of substituted pyridines. Correlation with basicity and with Hammett substituent constants}, journal = {Journal of Molecular Structure-Theochem}, volume = {863}, number = {1-3}, year = {2008}, note = {ISI Document Delivery No.: 342NSTimes Cited: 6Cited Reference Count: 23Takahata, Yuji Wulfman, Carl E. Chong, Delano P.}, month = {Aug}, pages = {33-38}, type = {Article}, 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.}, keywords = {acid dissociation, BENZENE-DERIVATIVES, CEBE shifts, DENSITY-FUNCTIONAL CALCULATION, DFT, Hammett substituent (sigma) constant, ionization processes, PARAMETERS, pyridines, SHIFTS, SIGMA CONSTANTS, SPECTROSCOPY}, isbn = {0166-1280}, url = {://000258791400006}, author = {Takahata, Y. and Wulfman, C. E. and Chong, D. P.} }