Polyoxometalate-Bridged Cu(I)- and Ag(I)-Thiacalix[4]arene Dimers for Heterogeneous Catalytic Oxidative Desulfurization and Azide–Alkyne “Click” Reaction

Abstract

Two remarkable polyoxometalate-bridged Cu(I)- and Ag(I)-thiacalix[4]arene dimers, namely, [Cu₄(SiW₁₂O₄₀)(L)₂(DMF)₂]·2EtOH·DMF (<b>1-Cu</b>) and [Ag₄(PMo₁₂O₄₀)(L)₂]·OH (<b>1-Ag</b>), were prepared by using a new thiacalix[4]arene, metal cation and polyoxometalate (L = tetra[2-(ethylthio)-1-methyl-1<i>H</i>-imidazole]-thiacalix[4]arene). In <b>1-Cu</b> and <b>1-Ag</b>, two thiacalix[4]arenes were linked together by one [SiW₁₂O₄₀]^4- or [PMo₁₂O₄₀]^3- anion via two metal cations to give a molecular dimer. Further, adjacent dimers were extended into a high-dimensional supramolecular architecture through hydrogen bonds. Markedly, these molecular dimers are exceedingly stable in organic solvents and then were employed as efficient catalysts for catalytic oxidation desulfurization as well as the azide-alkyne "click" reaction.