The Effect of Intramolecular Hydrogen Bond Type on the Gas-Phase Deprotonation of ortho-Substituted Benzenesulfonic Acids. A Density Functional Theory Study
| Autor: | Georgiy V. Girichev, Anastasiya V. Ignatova, Sergey N. Ivanov, M. S. Fedorov, Nina I. Giricheva |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
intramolecular hydrogen bond
Substituent Pharmaceutical Science Medicinal chemistry Analytical Chemistry lcsh:QD241-441 conformer chemistry.chemical_compound Benzenesulfonic acid Deprotonation lcsh:Organic chemistry Drug Discovery Physical and Theoretical Chemistry Conformational isomerism deprotonation energy integumentary system Hydrogen bond organic chemicals Organic Chemistry benzenesulfonic acids ortho-effect Acceptor chemistry Chemistry (miscellaneous) Intramolecular force Molecular Medicine Density functional theory |
| Zdroj: | Molecules Volume 25 Issue 24 Molecules, Vol 25, Iss 5806, p 5806 (2020) |
| ISSN: | 1420-3049 |
| DOI: | 10.3390/molecules25245806 |
| Popis: | Structural factors have been identified that determine the gas-phase acidity of ortho-substituted benzenesulfonic acid, 2-XC6H4&ndash SO3H, (X = &ndash SO3H, &ndash COOH, &ndash NO2, &ndash SO2F, &ndash C&equiv N, &ndash NH2, &ndash CH3, &ndash OCH3, &ndash N(CH3)2, &ndash OH). The DFT/B3LYP/cc-pVTZ method was used to perform conformational analysis and study the structural features of the molecular and deprotonated forms of these compounds. It has been shown that many of the conformers may contain anintramolecular hydrogen bond (IHB) between the sulfonic group and the substituent, and the sulfonic group can be an IHB donor or an acceptor. The Gibbs energies of gas-phase deprotonation &Delta rG0298 (kJ mol&ndash 1) were calculated for all compounds. It has been set that in ortho-substituted benzenesulfonic acids, the formation of various types of IHB is possible, having a significant effect on the &Delta rG0298 values of gas-phase deprotonation. If the &ndash SO3H group is the IHB donor, then an ion without an IHB is formed upon deprotonation, and the deprotonation energy increases. If this group is an IHB acceptor, then a significant decrease in &Delta rG0298 of gas-phase deprotonation is observed due to an increase in IHB strength and the A&minus anion additional stabilization. A proton donor ability comparative characteristic of the &ndash SO3H group in the studied ortho-substituted benzenesulfonic acids is given, and the &Delta rG0298 energies are compared with the corresponding values of ortho-substituted benzoic acids. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
| Nepřihlášeným uživatelům se plný text nezobrazuje | K zobrazení výsledku je třeba se přihlásit. |