Cation-mediated optical resolution and anticancer activity of chiral polyoxometalates built from entirely achiral building blocks.

We report the crystallization of homochiral polyoxometalate (POM) macroanions {CoSbO(HO)[Co(hmta)SbWO]} (, hmta = hexamethylenetetramine) the counter cation-mediated chiral symmetry breaking and asymmetric autocatalytic processes. In the presence of low Co concentrations both Δ- and Λ-enantiomers of formed in the reaction, crystallizing into the racemic crystal -. At a high Co concentration, the polyoxoanion enantiomers showed a high level of chiral recognition H-bonding interactions to crystallize into enantiopure crystals of Δ- or Λ-[Co(HO){CoSbO(HO)[Co(hmta)SbWO]}].

Inorganic crown ethers: sulfate-based Preyssler polyoxometalates.

A tungsten crown: The {SO(4)} units were introduced into the {W(30)} crown, resulting in a new Preyssler polyoxoanion {S(5)W(30)} with position-specific, guest, K(+) or Na(+) ions in its geometrical center. The as-prepared polyoxoanion exhibits an interesting ion-selective encapsulation of K(+) and Na(+) (see figure).