Stability order of the lanthanide chelates of two disubstituted 3-hydroxy-4H-pyran-4-ones in aqueous solution.
The stability constants of the 1:1 chelates formed by tervalent lanthanides with 2-bromo-3-hydroxy-6-(hydroxymethyl)-4H-pyran-4-one and 3-hydroxy-6-(hydroxymethyl)-2-iodo-4H-pyran-4-one were determined by spectrophotometric titration in aqueous potassium chloride solution at 25 degrees . The determinations were done at two different ionic strengths near 0.1 and the value at I = 0.1 was interpolated. The log beta(101) values of both complex series exhibit the same trend; the stability increases gradually with decrease in the ionic radius and shows a break at Gd and Lu.
Petrola
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R
Division of Analytical Chemistry, University of Helsinki, Vuorikatu 20, SF-00100 Helsinki, Finland.
Lampen
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P
Lindroos
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S