Tautomerism of 4-phenyl-2,4-dioxobutanoic acid. Insights from pH ramping NMR study and quantum chemical calculations
Само за регистроване кориснике
2018
Аутори
Cvijetić, Ilija
Pešić, Miloš P.

Todorov, Miljana D.
Drakulić, Branko

Juranić, Ivan

Verbić, Tatjana

Zloh, Mire

Чланак у часопису (Објављена верзија)

Метаподаци
Приказ свих података о документуАпстракт
Aryldiketo acids (ADKs) exhibit the variety of biological activities, mainly due to large affinity toward divalent metal ions. Metal complexation ability of ADKs, as well as interactions with proteins, depend on tautomeric form present in solution. The main aim of this study was to fully explore the tautomeric preferences of 4-phenyl-2,4-dioxobutanoic acid (4PDA), as ADKs representative, in aqueous media at different pH values. 1D and 2D NMR spectroscopy in combination with quantum chemical calculations was applied in order to better understand the tautomeric preferences of 4PDA. The data in highly acidic media are especially interesting since there are no such findings in the literature due to low solubility of ADKs in molecular form. At low pH values, where 4PDA is unionized, the most abundant tautomeric form is enol with keto group closer to phenyl ring. At higher pH values, mixture of two 4PDA ionic forms coexists in solution. Their ratio calculated according to NMR data fits the v...alues predicted using two experimentally determined pK (a) values. Based on the complexity of H-1 NMR spectrum of monoanionic 4PDA form, coexistence of two stable rotamers was assumed. In an alkaline media, 4PDA is mostly present in dianionic form. As pi-electrons of dianion are delocalized over an entire keto-enol moiety, spectral distinction between tautomers was not possible. Quantum chemical calculations were used to predict relative stability of tautomers. The predictions were in good accordance with experimental results only in case when explicit water molecule was included in calculations.
Кључне речи:
Aryldiketo acid / Keto-enol tautomerism / NMR spectroscopy / Quantum chemical calculationsИзвор:
Structural Chemistry, 2018, 29, 2, 423-434Издавач:
- Springer/Plenum Publishers, New York
Финансирање / пројекти:
Напомена:
- The peer-reviewed version: http://cer.ihtm.bg.ac.rs/handle/123456789/2694
DOI: 10.1007/s11224-017-1039-3
ISSN: 1040-0400
WoS: 000427405400005
Scopus: 2-s2.0-85030176327
Институција/група
IHTMTY - JOUR AU - Cvijetić, Ilija AU - Pešić, Miloš P. AU - Todorov, Miljana D. AU - Drakulić, Branko AU - Juranić, Ivan AU - Verbić, Tatjana AU - Zloh, Mire PY - 2018 UR - https://cer.ihtm.bg.ac.rs/handle/123456789/2693 AB - Aryldiketo acids (ADKs) exhibit the variety of biological activities, mainly due to large affinity toward divalent metal ions. Metal complexation ability of ADKs, as well as interactions with proteins, depend on tautomeric form present in solution. The main aim of this study was to fully explore the tautomeric preferences of 4-phenyl-2,4-dioxobutanoic acid (4PDA), as ADKs representative, in aqueous media at different pH values. 1D and 2D NMR spectroscopy in combination with quantum chemical calculations was applied in order to better understand the tautomeric preferences of 4PDA. The data in highly acidic media are especially interesting since there are no such findings in the literature due to low solubility of ADKs in molecular form. At low pH values, where 4PDA is unionized, the most abundant tautomeric form is enol with keto group closer to phenyl ring. At higher pH values, mixture of two 4PDA ionic forms coexists in solution. Their ratio calculated according to NMR data fits the values predicted using two experimentally determined pK (a) values. Based on the complexity of H-1 NMR spectrum of monoanionic 4PDA form, coexistence of two stable rotamers was assumed. In an alkaline media, 4PDA is mostly present in dianionic form. As pi-electrons of dianion are delocalized over an entire keto-enol moiety, spectral distinction between tautomers was not possible. Quantum chemical calculations were used to predict relative stability of tautomers. The predictions were in good accordance with experimental results only in case when explicit water molecule was included in calculations. PB - Springer/Plenum Publishers, New York T2 - Structural Chemistry T1 - Tautomerism of 4-phenyl-2,4-dioxobutanoic acid. Insights from pH ramping NMR study and quantum chemical calculations VL - 29 IS - 2 SP - 423 EP - 434 DO - 10.1007/s11224-017-1039-3 ER -
@article{ author = "Cvijetić, Ilija and Pešić, Miloš P. and Todorov, Miljana D. and Drakulić, Branko and Juranić, Ivan and Verbić, Tatjana and Zloh, Mire", year = "2018", abstract = "Aryldiketo acids (ADKs) exhibit the variety of biological activities, mainly due to large affinity toward divalent metal ions. Metal complexation ability of ADKs, as well as interactions with proteins, depend on tautomeric form present in solution. The main aim of this study was to fully explore the tautomeric preferences of 4-phenyl-2,4-dioxobutanoic acid (4PDA), as ADKs representative, in aqueous media at different pH values. 1D and 2D NMR spectroscopy in combination with quantum chemical calculations was applied in order to better understand the tautomeric preferences of 4PDA. The data in highly acidic media are especially interesting since there are no such findings in the literature due to low solubility of ADKs in molecular form. At low pH values, where 4PDA is unionized, the most abundant tautomeric form is enol with keto group closer to phenyl ring. At higher pH values, mixture of two 4PDA ionic forms coexists in solution. Their ratio calculated according to NMR data fits the values predicted using two experimentally determined pK (a) values. Based on the complexity of H-1 NMR spectrum of monoanionic 4PDA form, coexistence of two stable rotamers was assumed. In an alkaline media, 4PDA is mostly present in dianionic form. As pi-electrons of dianion are delocalized over an entire keto-enol moiety, spectral distinction between tautomers was not possible. Quantum chemical calculations were used to predict relative stability of tautomers. The predictions were in good accordance with experimental results only in case when explicit water molecule was included in calculations.", publisher = "Springer/Plenum Publishers, New York", journal = "Structural Chemistry", title = "Tautomerism of 4-phenyl-2,4-dioxobutanoic acid. Insights from pH ramping NMR study and quantum chemical calculations", volume = "29", number = "2", pages = "423-434", doi = "10.1007/s11224-017-1039-3" }
Cvijetić, I., Pešić, M. P., Todorov, M. D., Drakulić, B., Juranić, I., Verbić, T.,& Zloh, M.. (2018). Tautomerism of 4-phenyl-2,4-dioxobutanoic acid. Insights from pH ramping NMR study and quantum chemical calculations. in Structural Chemistry Springer/Plenum Publishers, New York., 29(2), 423-434. https://doi.org/10.1007/s11224-017-1039-3
Cvijetić I, Pešić MP, Todorov MD, Drakulić B, Juranić I, Verbić T, Zloh M. Tautomerism of 4-phenyl-2,4-dioxobutanoic acid. Insights from pH ramping NMR study and quantum chemical calculations. in Structural Chemistry. 2018;29(2):423-434. doi:10.1007/s11224-017-1039-3 .
Cvijetić, Ilija, Pešić, Miloš P., Todorov, Miljana D., Drakulić, Branko, Juranić, Ivan, Verbić, Tatjana, Zloh, Mire, "Tautomerism of 4-phenyl-2,4-dioxobutanoic acid. Insights from pH ramping NMR study and quantum chemical calculations" in Structural Chemistry, 29, no. 2 (2018):423-434, https://doi.org/10.1007/s11224-017-1039-3 . .