Polyoxometalate-supported Y- and Yb^III-hydroxo/oxo clusters from carbonate-assisted hydrolysis

Carbonate-assisted hydrolysis of Y or Yb^III ions in the presence of the trivacant Wells-Dawson polyoxo-anion, α-[P₂W ₁₅O₅₆]^12-, produced two polyoxometalate- supported Y- or Yb^III-hydroxo/oxo clusters, which have been characterized by single-crystal X-ray structure determination. The structure of the Y complex consists of a distorted Y₄(OH)₄ cubane cluster encapsulated by two lacunary α-[P₂W₁₅O ₅₆]^12- units, while the Yb cluster features a hexametallic core centered around a μ₆-oxo atom with each Yb^III triangular face capped by an oxo or a hydroxo group. Magnetization measurements of the ytterbium(III) derivative suggested that intermolecular dipolar exchange is present at low temperatures (below 15 K). Despite its absence in the structures themselves, control experiments show that carbonate not only functions in the hydrolysis, it also influences the structure of the complexes by complexation to yttrium and the f-block elements.