{Mo₁₂₆ W₃₀ }: Polyoxometalate Cages Shaped by π-π Interactions

Area of Science:

• Inorganic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Polyoxometalates (POMs) are versatile nanoscale inorganic clusters.
• Templated synthesis offers a route to complex POM architectures.
• π-conjugated ligands can direct the self-assembly of POMs.

Purpose of the Study:

• To synthesize novel giant polyoxometalate cages.
• To investigate the role of π-conjugated ligands in templating POM formation.
• To explore the stability and functionalization potential of these cages.

Main Methods:

• Solvothermal synthesis using {Mo126W30} precursors.
• Templating with planar π-conjugated aromatic carboxylates (e.g., 1,3,5-benzenetricarboxylate, 5-nitroisophthalate).
• Nuclear Magnetic Resonance (NMR) spectroscopy for structural confirmation and stability assessment.

Main Results:

• Formation of giant {Mo126W30} polyoxometalate cages.
• Inorganic shells incorporate 18 stacked aromatic carboxylate units.
• Assembly is stabilized by π-π interactions between ligands.
• Cages exhibit stability in solution.
• Successful postsynthetic replacement of internal aromatic templates with aliphatic dicarboxylates.

Conclusions:

• Giant polyoxometalate cages can be templated by π-conjugated ligands.
• The cage structure is robust and stable in solution.
• Postsynthetic modification allows for endo-functionalization, opening avenues for new reactivity studies.