Dehydration from tris[beta-diketonato]lanthanoids (III) on the 1,10-phenanthroline adduct formation across lanthanoid series

The residual hydration number of the metal ion in the 1,10-phenanthroline adducts of tris [1,1,1-trifluoro-5,5´-dimethyl-2,4-hexanedionato]lanthanoids in chloroform has been determined by coulometric Karl-Fischer titration and also by the luminescence lifetime of europium(III) in the complex. The residual hydration number was essentially zero for all lanthanoids across the series. This data and the hydration number of the lanthanoids(III) complexed with the beta-diketone can be used to explain the trend of the variation of the formation constants of the adducts across the lanthanoid series.