ПРОТОЛІТИЧНА РІВНОВАГА ТЕТРА- І ПЕНТА- НІТРОФЛУОРЕСЦЕЇНУ У БІНАРНОМУ РОЗЧИННИКУ АЦЕТОНІТРИЛ — ДИМЕТИЛСУЛЬФОКСИД (МАСОВЕ СПІВІДНОШЕННЯ 96 : 4)
In this paper, the acid-base and tautomeric equilibria of four nitrofluorescein dyes, 2,4,5,7-tetranitrofluorescein, 2,4,5,7,4’-pentanitrofluorescein, 2,4,5,7,5’-pentanitrofluorescein, and 2,4,5,7-tetranitrofluorescein methyl ester, were studied. As reaction media, a binary solvent acetonitrile – di...
Gespeichert in:
| Datum: | 2021 |
|---|---|
| Hauptverfasser: | , , , |
| Format: | Artikel |
| Sprache: | English |
| Veröffentlicht: |
V.I.Vernadsky Institute of General and Inorganic Chemistry
2021
|
| Online Zugang: | https://ucj.org.ua/index.php/journal/article/view/311 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| Назва журналу: | Ukrainian Chemistry Journal |
Institution
Ukrainian Chemistry Journal| id |
oai:ojs2.1444248.nisspano.web.hosting-test.net:article-311 |
|---|---|
| record_format |
ojs |
| spelling |
oai:ojs2.1444248.nisspano.web.hosting-test.net:article-3112021-08-02T08:57:29Z PROTOLYTIC EQUILIBRIUM OF TETRA- AND PENTANITROFLUORESCEINS IN A BINARY SOLVENT ACETONITRILE – DIMETHYL SULFOXIDE (MASS RATIO 96 : 4) ПРОТОЛІТИЧНА РІВНОВАГА ТЕТРА- І ПЕНТА- НІТРОФЛУОРЕСЦЕЇНУ У БІНАРНОМУ РОЗЧИННИКУ АЦЕТОНІТРИЛ — ДИМЕТИЛСУЛЬФОКСИД (МАСОВЕ СПІВІДНОШЕННЯ 96 : 4) Moskaeva, Elena Mosharenkova, Ahina Shekhovtsov, Sergey Mchedlov-Petrossyan, Nikolay nitrofluorescein dyes, acetonitrile-DMSO binary solvent, buffer solutions, absorption spectra, dissociation constants, tautomerism, anionic lactones. In this paper, the acid-base and tautomeric equilibria of four nitrofluorescein dyes, 2,4,5,7-tetranitrofluorescein, 2,4,5,7,4’-pentanitrofluorescein, 2,4,5,7,5’-pentanitrofluorescein, and 2,4,5,7-tetranitrofluorescein methyl ester, were studied. As reaction media, a binary solvent acetonitrile – dimethyl sulfoxide (96 : 4 by mass) was used. The acidity scale in this solvent was established previously. The indices of the dissociation constants of the dyes were determined using the spectrophotometric method. Interpreting the values requires an understanding of the state of tautomeric equilibria. The behavior of these compounds differs significantly from that of other fluorescein dyes, e.g., halogen derivatives. In the case of the first three compounds, i.e., for dyes with a free carboxylic group, the lactonic structure is predominant not only for the neutral form, but even for the double-charged anion. The single-charged anionic form exists as an equilibrium mixture of a colored (and fluorescent) tautomer and an almost colorless lactone. The fourth compound with esterified carboxylic group exhibits extreme stability in its anionic form. Evaluation of the tautomerization constants made it possible to calculate the microscopic equilibrium constants of the stepwise dissociation of dye lactones, k1L and k2L. The consideration of the difference (pk2L – pk1L) allowed estimating the effective relative permittivity of the space between the ionizing groups basing on the Bjerrum – Kirkwood – Westheimer equation. Tautomerism of anions was discussed from the point of view of stabilization of symmetric structures. V.I.Vernadsky Institute of General and Inorganic Chemistry 2021-06-25 Article Article Physical chemistry Физическая xимия Фізична xімія application/pdf https://ucj.org.ua/index.php/journal/article/view/311 10.33609/2708-129X.87.05.2021.25-37 Ukrainian Chemistry Journal; Vol 87 No 5 (2021): Ukrainian Chemistry Journal; 25-37 Украинский химический журнал; Том 87 № 5 (2021): Ukrainian Chemistry Journal; 25-37 Український хімічний журнал; Том 87 № 5 (2021): Український хімічний журнал; 25-37 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/311/170 |
| institution |
Ukrainian Chemistry Journal |
| baseUrl_str |
|
| datestamp_date |
2021-08-02T08:57:29Z |
| collection |
OJS |
| language |
English |
| topic_facet |
nitrofluorescein dyes acetonitrile-DMSO binary solvent buffer solutions absorption spectra dissociation constants tautomerism anionic lactones. |
| format |
Article |
| author |
Moskaeva, Elena Mosharenkova, Ahina Shekhovtsov, Sergey Mchedlov-Petrossyan, Nikolay |
| spellingShingle |
Moskaeva, Elena Mosharenkova, Ahina Shekhovtsov, Sergey Mchedlov-Petrossyan, Nikolay ПРОТОЛІТИЧНА РІВНОВАГА ТЕТРА- І ПЕНТА- НІТРОФЛУОРЕСЦЕЇНУ У БІНАРНОМУ РОЗЧИННИКУ АЦЕТОНІТРИЛ — ДИМЕТИЛСУЛЬФОКСИД (МАСОВЕ СПІВІДНОШЕННЯ 96 : 4) |
| author_facet |
Moskaeva, Elena Mosharenkova, Ahina Shekhovtsov, Sergey Mchedlov-Petrossyan, Nikolay |
| author_sort |
Moskaeva, Elena |
| title |
ПРОТОЛІТИЧНА РІВНОВАГА ТЕТРА- І ПЕНТА- НІТРОФЛУОРЕСЦЕЇНУ У БІНАРНОМУ РОЗЧИННИКУ АЦЕТОНІТРИЛ — ДИМЕТИЛСУЛЬФОКСИД (МАСОВЕ СПІВІДНОШЕННЯ 96 : 4) |
| title_short |
ПРОТОЛІТИЧНА РІВНОВАГА ТЕТРА- І ПЕНТА- НІТРОФЛУОРЕСЦЕЇНУ У БІНАРНОМУ РОЗЧИННИКУ АЦЕТОНІТРИЛ — ДИМЕТИЛСУЛЬФОКСИД (МАСОВЕ СПІВІДНОШЕННЯ 96 : 4) |
| title_full |
ПРОТОЛІТИЧНА РІВНОВАГА ТЕТРА- І ПЕНТА- НІТРОФЛУОРЕСЦЕЇНУ У БІНАРНОМУ РОЗЧИННИКУ АЦЕТОНІТРИЛ — ДИМЕТИЛСУЛЬФОКСИД (МАСОВЕ СПІВІДНОШЕННЯ 96 : 4) |
| title_fullStr |
ПРОТОЛІТИЧНА РІВНОВАГА ТЕТРА- І ПЕНТА- НІТРОФЛУОРЕСЦЕЇНУ У БІНАРНОМУ РОЗЧИННИКУ АЦЕТОНІТРИЛ — ДИМЕТИЛСУЛЬФОКСИД (МАСОВЕ СПІВІДНОШЕННЯ 96 : 4) |
| title_full_unstemmed |
ПРОТОЛІТИЧНА РІВНОВАГА ТЕТРА- І ПЕНТА- НІТРОФЛУОРЕСЦЕЇНУ У БІНАРНОМУ РОЗЧИННИКУ АЦЕТОНІТРИЛ — ДИМЕТИЛСУЛЬФОКСИД (МАСОВЕ СПІВІДНОШЕННЯ 96 : 4) |
| title_sort |
протолітична рівновага тетра- і пента- нітрофлуоресцеїну у бінарному розчиннику ацетонітрил — диметилсульфоксид (масове співідношення 96 : 4) |
| title_alt |
PROTOLYTIC EQUILIBRIUM OF TETRA- AND PENTANITROFLUORESCEINS IN A BINARY SOLVENT ACETONITRILE – DIMETHYL SULFOXIDE (MASS RATIO 96 : 4) |
| description |
In this paper, the acid-base and tautomeric equilibria of four nitrofluorescein dyes, 2,4,5,7-tetranitrofluorescein, 2,4,5,7,4’-pentanitrofluorescein, 2,4,5,7,5’-pentanitrofluorescein, and 2,4,5,7-tetranitrofluorescein methyl ester, were studied. As reaction media, a binary solvent acetonitrile – dimethyl sulfoxide (96 : 4 by mass) was used. The acidity scale in this solvent was established previously. The indices of the dissociation constants of the dyes were determined using the spectrophotometric method.
Interpreting the values requires an understanding of the state of tautomeric equilibria. The behavior of these compounds differs significantly from that of other fluorescein dyes, e.g., halogen derivatives. In the case of the first three compounds, i.e., for dyes with a free carboxylic group, the lactonic structure is predominant not only for the neutral form, but even for the double-charged anion. The single-charged anionic form exists as an equilibrium mixture of a colored (and fluorescent) tautomer and an almost colorless lactone. The fourth compound with esterified carboxylic group exhibits extreme stability in its anionic form.
Evaluation of the tautomerization constants made it possible to calculate the microscopic equilibrium constants of the stepwise dissociation of dye lactones, k1L and k2L. The consideration of the difference (pk2L – pk1L) allowed estimating the effective relative permittivity of the space between the ionizing groups basing on the Bjerrum – Kirkwood – Westheimer equation. Tautomerism of anions was discussed from the point of view of stabilization of symmetric structures. |
| publisher |
V.I.Vernadsky Institute of General and Inorganic Chemistry |
| publishDate |
2021 |
| url |
https://ucj.org.ua/index.php/journal/article/view/311 |
| work_keys_str_mv |
AT moskaevaelena protolyticequilibriumoftetraandpentanitrofluoresceinsinabinarysolventacetonitriledimethylsulfoxidemassratio964 AT mosharenkovaahina protolyticequilibriumoftetraandpentanitrofluoresceinsinabinarysolventacetonitriledimethylsulfoxidemassratio964 AT shekhovtsovsergey protolyticequilibriumoftetraandpentanitrofluoresceinsinabinarysolventacetonitriledimethylsulfoxidemassratio964 AT mchedlovpetrossyannikolay protolyticequilibriumoftetraandpentanitrofluoresceinsinabinarysolventacetonitriledimethylsulfoxidemassratio964 AT moskaevaelena protolítičnarívnovagatetraípentanítrofluoresceínuubínarnomurozčinnikuacetonítrildimetilsulʹfoksidmasovespívídnošennâ964 AT mosharenkovaahina protolítičnarívnovagatetraípentanítrofluoresceínuubínarnomurozčinnikuacetonítrildimetilsulʹfoksidmasovespívídnošennâ964 AT shekhovtsovsergey protolítičnarívnovagatetraípentanítrofluoresceínuubínarnomurozčinnikuacetonítrildimetilsulʹfoksidmasovespívídnošennâ964 AT mchedlovpetrossyannikolay protolítičnarívnovagatetraípentanítrofluoresceínuubínarnomurozčinnikuacetonítrildimetilsulʹfoksidmasovespívídnošennâ964 |
| first_indexed |
2025-09-24T17:43:39Z |
| last_indexed |
2025-09-24T17:43:39Z |
| _version_ |
1844168170442588160 |