Comparative assessment of the direct and isodesmic methods for pKa calculation of monocarboxylic acids using density functional theory

Autor(es)

Dutra, Felipe Ribeiro ; Custodio, Rogerio

• Tipo de documento: Artigo Científico
• Fonte: COMPUTATIONAL AND THEORETICAL CHEMISTRY; v. 1237, p. 10-pg., 2024-05-07.

Resumo

This study utilizes direct and isodesmic methods to determine the pKa of monocarboxylic acids. Twenty-four density functionals are tested using Dunning's aug-cc-pVDZ and aug-cc-pVTZ basis sets, incorporating the SMD model for implicit solvent effects and two explicit water molecules near the carboxyl group. Both methods achieve mean absolute errors below 0.5 pKa units, with hybrid functionals showing superior performance, while local density functionals also yield significant results. The comparative effectiveness of aug-cc-pVTZ and aug-ccpVDZ is assessed. The selection of appropriate training sets for the direct method and reference acids for the isodesmic method is crucial, with diverse acids in the training set reducing errors in the direct method and closely related reference acids enhancing precision in the isodesmic method. B3PW91 exhibited particularly outstanding performance, proving to be the most reliable for accurate pKa predictions across different setups. (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
• Processo FAPESP: 21/03201-3 - Estudo do método direto para o cálculo de pKa para diferentes espécies multipróticas a partir de cálculos quânticos
• Beneficiário: Felipe Ribeiro Dutra
• Modalidade de apoio: Bolsas no Brasil - Doutorado