Assessment of pK(a) Determination for Monocarboxylic Acids with an Accurate Theoretical Composite Method: G4CEP

Autor(es)

Silva, Cleuton de Souza ^{[1, 2]} ; Custodio, Rogerio ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Quim, BR-13083970 Campinas, SP - Brazil

^[2] Univ Fed Amazonas, Inst Ciencias Exatas & Tecnol, Campus Itacoatiara, BR-69100021 Itacoatiara, Amazonas - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry A; v. 123, n. 38, p. 8314-8320, SEP 26 2019.
• Citações Web of Science: 0

Resumo

For 22 monoprotic acids, pK(a) values were calculated using the G4CEP composite theory. The solvation effect was included considering the continuous SMD solvation model; SMD and one explicit water molecule; and SMD, one water molecule, and linear correction with respect to the experimental pK(a) values. The three tests provided mean absolute errors equal to 0.83, 0.51, and 0.30 plc units, respectively, indicating excellent performance of the G4CEP method. Comparison with density functional theory at the B3LYP and BMK levels showed that these results are quickly obtained but with a significant error. The best performance of the functionals was obtained from the combination of SMD, one explicit water molecule, linear regression correction, and basis set including diffuse functions. However, the dispersion of the results with DFT can lead to deviations of up to two pK(a) units, whereas for G4CEP the largest deviations seldom exceed one pK(a) unit. (AU)

• Processo FAPESP: 13/08293-7 - CECC - Centro de Engenharia e Ciências Computacionais
• Beneficiário: Munir Salomao Skaf
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 17/11485-6 - Desenvolvimentos computacionais e teóricos baseados em métodos ab initio e na Teoria do Funcional de Densidade
• Beneficiário: Rogério Custodio
• Modalidade de apoio: Auxílio à Pesquisa - Regular