A High-Nuclearity “Celtic-Ring” Isopolyoxotungstate, [H₁₂W₃₆O₁₂₀]^12-, That Captures Trace Potassium Ions

A high-nuclearity {W36} isopolyoxotungstate cluster, [H12W36O120]12-, with a triangular shape has been isolated by using an encapsulating organic cation, protonated triethanolamine. In analogy to an 18-crown-6 crown ether, the cluster captures a potassium ion, present in trace amounts in the reaction system, within its cavity. DFT calculations suggest that the distribution of partial atomic charges over the oxygen framework shows maxima at certain “hotspot” sites, which imply possible routes for further cluster growth based on the {W36} system.