ACID-BASE PROPERTIES OF ALKYLENE­DIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS

The acid-base characteristics of ethylenediaminetetra(methylenephosphonic) (edtmp), tetramethylenediaminetetra(methylenephosphonic) (tetdtmp) and pentamethylenediaminetetra(methylenephosphonic) (pendtmp) acids were investigated by means of pH-potentiometry and 31P NMR spectroscopy. Calculated and es...

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Дата:2023
Автори: Kozachkova, Oleksandra, Tsaryk, Nataliya, Pekhnyo, Vasyl, Trachevskij, Volodymyr, Kocharovska, Olga, Palchyk, Oleksii
Формат: Стаття
Мова:English
Опубліковано: V.I.Vernadsky Institute of General and Inorganic Chemistry 2023
Онлайн доступ:https://ucj.org.ua/index.php/journal/article/view/536
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Назва журналу:Ukrainian Chemistry Journal

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Ukrainian Chemistry Journal
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spelling oai:ojs2.1444248.nisspano.web.hosting-test.net:article-5362023-06-21T06:48:35Z ACID-BASE PROPERTIES OF ALKYLENE­DIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS Kozachkova, Oleksandra Tsaryk, Nataliya Pekhnyo, Vasyl Trachevskij, Volodymyr Kocharovska, Olga Palchyk, Oleksii alkylenediaminetetra(methylene­phosphonic) acids, acid dissociation constants The acid-base characteristics of ethylenediaminetetra(methylenephosphonic) (edtmp), tetramethylenediaminetetra(methylenephosphonic) (tetdtmp) and pentamethylenediaminetetra(methylenephosphonic) (pendtmp) acids were investigated by means of pH-potentiometry and 31P NMR spectroscopy. Calculated and estimated values of acid dissociation constants (pK) for edtmp (рК1<2, рК2<2, рК3=3.07, рК4=5.17, рК5=6.52, рК6=7.97, рК7=9.65, рК8=10.94), for tetdtmp (рК1<2, рК2=4.48, рК3=5.34, рК4=6.13, рК5=6.66, рК6=10.08, рК7~11.4, рК8~11.5) and for pendtmp (рК1<2, рК2=4.22, рК3=5.56, рК4=6.16, рК5=7.66, рК6=10.99, рК7~11.5, рК8~11.6) were obtained. The values of the acid dissociation constants indicate a decrease in the acidity of phosphonic groups and an increase in the basicity of amino groups with increasing hydrocarbon chain length between the two nitrogen atoms in the edtmp, tetdtmp, and pendtmpseries. Based on the values of the calculated constants for the formation of anions of tetra­phosphonic acids, diagrams of the distribution of their equilibrium concentrations depending on pH were constructed, which indicate the state of acid-base equilibrium, the charge and the ratio of concentrations between anions with different degrees of protonation at certain pH values. According to the data of 31P NMR spectro­scopy, the formation of intramolecular hydrogen bonds between the deprotonated oxygen atoms of one amino(methylphosphonic) group with protonated nitrogen atom of another amino(methylphosphonic) group was established in the case of edtmp. In the case of pendtmp and tetdtmp, the formation of intermolecular hydrogen bonds between distant amino(me­thyl­phosphonic) groups is impossible due to the presence of steric hindrances. V.I.Vernadsky Institute of General and Inorganic Chemistry 2023-04-28 Article Article Inorganic Chemistry Неорганическая химия Неорганічна хімія application/pdf https://ucj.org.ua/index.php/journal/article/view/536 10.33609/2708-129X.89.03.2023.3-14 Ukrainian Chemistry Journal; Vol. 89 No. 3 (2023): Ukrainian Chemistry Journal; 3-14 Украинский химический журнал; Том 89 № 3 (2023): Ukrainian Chemistry Journal; 3-14 Український хімічний журнал; Том 89 № 3 (2023): Український хімічний журнал; 3-14 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/536/271
institution Ukrainian Chemistry Journal
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datestamp_date 2023-06-21T06:48:35Z
collection OJS
language English
topic_facet alkylenediaminetetra(methylene­phosphonic) acids
acid dissociation constants
format Article
author Kozachkova, Oleksandra
Tsaryk, Nataliya
Pekhnyo, Vasyl
Trachevskij, Volodymyr
Kocharovska, Olga
Palchyk, Oleksii
spellingShingle Kozachkova, Oleksandra
Tsaryk, Nataliya
Pekhnyo, Vasyl
Trachevskij, Volodymyr
Kocharovska, Olga
Palchyk, Oleksii
ACID-BASE PROPERTIES OF ALKYLENE­DIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS
author_facet Kozachkova, Oleksandra
Tsaryk, Nataliya
Pekhnyo, Vasyl
Trachevskij, Volodymyr
Kocharovska, Olga
Palchyk, Oleksii
author_sort Kozachkova, Oleksandra
title ACID-BASE PROPERTIES OF ALKYLENE­DIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS
title_short ACID-BASE PROPERTIES OF ALKYLENE­DIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS
title_full ACID-BASE PROPERTIES OF ALKYLENE­DIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS
title_fullStr ACID-BASE PROPERTIES OF ALKYLENE­DIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS
title_full_unstemmed ACID-BASE PROPERTIES OF ALKYLENE­DIAMINETETRA (METHYLENEPHOSPHONIC) ACIDS
title_sort acid-base properties of alkylene­diaminetetra (methylenephosphonic) acids
description The acid-base characteristics of ethylenediaminetetra(methylenephosphonic) (edtmp), tetramethylenediaminetetra(methylenephosphonic) (tetdtmp) and pentamethylenediaminetetra(methylenephosphonic) (pendtmp) acids were investigated by means of pH-potentiometry and 31P NMR spectroscopy. Calculated and estimated values of acid dissociation constants (pK) for edtmp (рК1<2, рК2<2, рК3=3.07, рК4=5.17, рК5=6.52, рК6=7.97, рК7=9.65, рК8=10.94), for tetdtmp (рК1<2, рК2=4.48, рК3=5.34, рК4=6.13, рК5=6.66, рК6=10.08, рК7~11.4, рК8~11.5) and for pendtmp (рК1<2, рК2=4.22, рК3=5.56, рК4=6.16, рК5=7.66, рК6=10.99, рК7~11.5, рК8~11.6) were obtained. The values of the acid dissociation constants indicate a decrease in the acidity of phosphonic groups and an increase in the basicity of amino groups with increasing hydrocarbon chain length between the two nitrogen atoms in the edtmp, tetdtmp, and pendtmpseries. Based on the values of the calculated constants for the formation of anions of tetra­phosphonic acids, diagrams of the distribution of their equilibrium concentrations depending on pH were constructed, which indicate the state of acid-base equilibrium, the charge and the ratio of concentrations between anions with different degrees of protonation at certain pH values. According to the data of 31P NMR spectro­scopy, the formation of intramolecular hydrogen bonds between the deprotonated oxygen atoms of one amino(methylphosphonic) group with protonated nitrogen atom of another amino(methylphosphonic) group was established in the case of edtmp. In the case of pendtmp and tetdtmp, the formation of intermolecular hydrogen bonds between distant amino(me­thyl­phosphonic) groups is impossible due to the presence of steric hindrances.
publisher V.I.Vernadsky Institute of General and Inorganic Chemistry
publishDate 2023
url https://ucj.org.ua/index.php/journal/article/view/536
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first_indexed 2025-09-24T17:43:49Z
last_indexed 2025-09-24T17:43:49Z
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