ISSN:
0749-1581
Keywords:
All-(E)-retinoic acid
;
13C NMR
;
Monomer-dimer equilibrium
;
Enthalpy change
;
Entropy change
;
Temperature dependence
;
Self-association
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The monomer-dimer equilibrium of retinoic acid in carbon tetrachloride was studied by 1H and 13C NMR spectroscopy. The dimer dissociation constant at 24°C was determined to be 0.38 mM from a fit of the changes in the carboxylic acid carbon chemical shift as a function of concentration. The temperature dependence of the equilibrium constant obtained from the 13C NMR signals was used to determine the enthalpy (8.0 kcal mol-1) and entropy (12 cal mol-1 K-1) changes for the dimer dissociation process. These results were shown to be more precise than the values obtained from the carboxylic acid proton resonance.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260280306
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