Polarographic Studies on Complex Formation of Cryptand[2.2] and a Macrocyclic Polythioetheramine with Alkali or Alkaline-Earth Metal Ions in Acetonitrile
Access this Article
Search this Article
The formation constants for 1:1 complexes between Li<sup>+</sup> or Na<sup>+</sup> and a monocyclic polyetherdiamine, cryptand[2.2], were evaluated in acetonitrile at 25±0.2°C by three d.c. polarographic analyses: the positive shift in <i>E</i><sub>1/2</sub> of the anodic (mercury dissolution) wave induced from cryptand[2.2] in the presence of a large excess of LiClO<sub>4</sub> and NaClO<sub>4</sub>; the positive shift in <i>E</i><sub>1/2</sub> of the cathodic wave of the [HgL]<sup>2+</sup> complex (L=cryptand[2.2]) in the presence of a large excess of alkali metal ions; and the negative shift of the cathodic wave of Li<sup>+</sup>or Na<sup>+</sup> in the presence of a large excess of cryptand[2.2]. The above three analyses gave complex formation constants that were consistent with each other within experimental error. In a less solvating medium (benzonitrile), stronger interactions were observed between the cations and cryptand[2.2]. The interaction between alkali metal ions and 1, 10-diaza-4, 7, 13, 16-tetrathiacyclooctadecane (ATCO) was very small, even in benzonitrile. The complex formation constants of [SrL′]<sup>2+</sup> and [BaL′]<sup>2+</sup> (L′=ATCO) in acetonitrile were both ca.10<sup>2.5</sup> by the first two methods mentioned above.
- Analytical Sciences
Analytical Sciences 11(3), 419-424, 1995-07-10
The Japan Society for Analytical Chemistry