Polarographic Studies on Complex Formation of Cryptand[2.2] and a Macrocyclic Polythioetheramine with Alkali or Alkaline-Earth Metal Ions in Acetonitrile

The formation constants for 1 : 1 complexes between Li + or Na + 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 E 1/2 of the anodic (mercury dissolution) wave induced from cryptand[2.2] in the presence of a large excess of LiClO 4 and NaClO 4 ; the positive shift in E 1/2 of the cathodic wave of the [HgL] 2+ 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 + or Na + 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] 2+ and [BaL] 2+ (L'=ATCO) in acetonitrile were both ca.10 2.5 by the first two methods mentioned above.