TY - JOUR
T1 - Determination and comparison of the thermodynamic quantities of U(VI) complexation with "aliphatic" and "aromatic" di-carboxylic acids by calorimetry
AU - Kirishima, Akira
AU - Sato, Nobuaki
N1 - Funding Information:
This study has been partially supported by the Grant-in-Aid for Young Scientists (B) of The Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT).
PY - 2014/3
Y1 - 2014/3
N2 - The thermodynamic quantities (ΔG, ΔH, ΔS) of complex formation of U(VI) with three "aliphatic" di-carboxylic acids, i.e. oxydiacetic acid (ODA), thiodiacetic acid (TDA), iminodiacetic acid (IDA), and three "aromatic" di-carboxylic acids, i.e. 2,5-furandicarboxylic acid (FDA), 2,5-thiophenedicarboxylic acid (TDCA) and dipicolinic acid (DPA) were determined by potentiometric titration and micro-calorimetric titration. The obtained thermodynamic quantities are compared with each other for the discussion of the effect of structural difference, i.e. aliphatic- and aromatic structure and types of central atom in the ligands on the complex formation thermodynamics. A clear tendency is observed in the complexation data between aliphatic- and aromatic ligands. The complexation of those aliphatic ligands are completely entropy driven, on the contrary, the enthalpy change is a certain driving force in the complexation of those aromatic ligands while entropy change also contributes to progress of the reaction. The ΔG, ΔH and ΔS of 1:1 IDA complex show remarkable difference from those of glutaric acid (GA) complex, while those of ODA and TDA complex are almost equal to those of GA complex, which seems to be attributed to the difference of the coordination mode.
AB - The thermodynamic quantities (ΔG, ΔH, ΔS) of complex formation of U(VI) with three "aliphatic" di-carboxylic acids, i.e. oxydiacetic acid (ODA), thiodiacetic acid (TDA), iminodiacetic acid (IDA), and three "aromatic" di-carboxylic acids, i.e. 2,5-furandicarboxylic acid (FDA), 2,5-thiophenedicarboxylic acid (TDCA) and dipicolinic acid (DPA) were determined by potentiometric titration and micro-calorimetric titration. The obtained thermodynamic quantities are compared with each other for the discussion of the effect of structural difference, i.e. aliphatic- and aromatic structure and types of central atom in the ligands on the complex formation thermodynamics. A clear tendency is observed in the complexation data between aliphatic- and aromatic ligands. The complexation of those aliphatic ligands are completely entropy driven, on the contrary, the enthalpy change is a certain driving force in the complexation of those aromatic ligands while entropy change also contributes to progress of the reaction. The ΔG, ΔH and ΔS of 1:1 IDA complex show remarkable difference from those of glutaric acid (GA) complex, while those of ODA and TDA complex are almost equal to those of GA complex, which seems to be attributed to the difference of the coordination mode.
KW - Calorimetry
KW - Dicarboxylic acid
KW - Enthalpy
KW - Stability constant
KW - Uranium(VI) complex
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U2 - 10.1016/j.jct.2013.11.011
DO - 10.1016/j.jct.2013.11.011
M3 - Article
AN - SCOPUS:84890074318
VL - 70
SP - 227
EP - 232
JO - Journal of Chemical Thermodynamics
JF - Journal of Chemical Thermodynamics
SN - 0021-9614
ER -