Naslov
Influence of different dielectric continuum solvent models on the accuracy of pKa Values

Autori
Glasovac, Zoran ; Eckert-Maksić, Mirjana ; Maksić, Zvonimir B.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
The 13th European Symposium on Organic Reactivity - Book of Abstracts / Burk, Peeter - Tartu, 2011

Skup
The 13th European Symposium on Organic Reactivity

Mjesto i datum
Tartu, Estonija, 11.09.2011. - 16.09.2011

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
pKa calculations; dielectric continuum solvent models

Sažetak
The most common computational approach for calculation of pKa values is based on the thermodynamical cycle. Within this approach, solvation energies (DeltaG_sol) can be calculated by various methods, of which dielectric continuum solvent models (DCSM) are particularly interesting because of their low demands for computer resources. However, in a series of papers Klamt and coworkers pointed to a systematic discrepancy between calculated and experimental pKa's, where parameters a and b significantly differ from the ideal values of 1 and [G°sol(H+) + DeltaG°^→*], respectively. To overcome this problem, we have employed linear correlation between experimental pKa's and the „reduced basicities“ (DeltaG'_a, sol) in acetonitrile. In continuation of this work, quest for the simplest, but yet the most adequate, DCSM for the calculation of pKa values of different nitrogen bases was conducted. Herein detailed analysis of quality of different DCS models applied will be presented. For this purpose, performance of several variants of PCM solvation models will be compared with that of COSMO, SMX and SS(V)PE approaches. Quality of each method will be discussed in terms of deviation of the regression parameters a and b (slope and intercept, respectively) from the ideal values. In addition, possibility of G°_sol(H^+) calculations from the intercept b will be presented. The latter is particularly important for the solvents for which no experimental data for G°_sol(H^+) is available in literature.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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