Solvent-tuned polyoxometalate-based supramolecular hybrids constructed from different metal-organic motifs: Various structures and adsorption properties for dyes

By changing the solvents, three polyoxometalate (POM)-based supramolecular hybrids, Co₂L₃]SiW₁₂O₄₀]·17H₂O (1), Co₂L₂(H₂O)₄]SiW₁₂O₄₀]·2EtOH·2H₂O (2) and Co₂L₃]SiW₁₂O₄₀]·9DMA·6H₂O (3), have been synthesized under hydrothermal or solvothermal conditions. All three hybrids show various supramolecular structures, which contain two kinds of different metal-organic motifs. A kind of metal-organic cationic cage Co₂L₃]⁴⁺ is formed in the presence of H₂O for 1, DMA/H₂O for 3, and a metal-organic cationic circle Co₂L₂]⁴⁺ is constructed in the presence of EtOH/H₂O for 2. That is to say, the solvents show a key role in tuning the architectures of metal-organic fragments and the final POM-based supramolecular structures. The adsorption properties of 1–3 for different organic dyes have also been investigated.