Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/54084
Type: Artigo de periódico
Title: Accurate calculation of N1s and C1s core electron binding energies of substituted pyridines. Correlation with basicity and with Hammett substituent constants
Author: Takahata, Y
Wulfman, CE
Chong, DP
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.
Subject: pyridines
CEBE shifts
DFT
Hammett substituent (sigma) constant
ionization processes
acid dissociation
Country: Holanda
Editor: Elsevier Science Bv
Rights: fechado
Identifier DOI: 10.1016/j.theochem.2008.05.009
Date Issue: 2008
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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