Nanotoroids or Coordination Networks: Molecular Constructs at the Mercy of Anions

Pyrogallol[4]arene (PgC) macrocycles, owing to their preorganized structures, are known to form dimeric (M₈L₂), hexameric (M₂₄L₆), and dodecameric (M₂₄L₁₂) nanocapsules, as well as coordination networks. However, the role of anions in the formation of varied geometries and stoichiometries of PgCs is understudied. In this study, we explore the assembly of pyrogallol[4]arene with strontium iodide, forming metal-organic nanotoroids (M₁₀L₈), and with strontium nitrate, which forms coordination networks. Preliminary fluorescence spectroscopy experiments with dyes such as coumarin 153 and Nile red confirm that these nanotoroidal channels can effectively host dye molecules, making them suitable for diverse applications, including drug delivery. Furthermore, the nanotoroids and surface defects of the crystals can serve as a template to grow gold nanosheets.