Efficient Catalytic Oxidative Desulfurization toward Thioether and Sulfur Mustard Stimulant by Polyoxomolybdate–Resorcin[4]arene-Based Metal–Organic Materials

Abstract

The design and synthesis of effective and recyclable oxidative desulfurization catalysts is of great importance in view of environmental protection and human health. Herein, a family of polyoxomolybdate-based inorganic-organic hybrid materials, namely, [Mn(TMR4A)(H₂O)₄][Mo₆O₁₉]·0.5CH₃CH₂OH·H₂O (<b>1</b>), [Ni(TMR4A)(H₂O)₄][Mo₆O₁₉]·0.5CH₃CH₂OH·H₂O (<b>2</b>), [Zn(TMR4A)(H₂O)₄][Mo₆O₁₉]·0.5CH₃CH₂OH·H₂O (<b>3</b>), and [Co₂(TMR4A)₂(H₂O)₄(β-Mo₈O₂₆)]·CH₃CN·12H₂O (<b>4</b>), were assembled by the functionalized resorcin[4]arene ligand (TMR4A) with polyoxomolybdate and metal ions under solvothermal conditions. In isostructural <b>1</b>-<b>3</b>, the [M(TMR4A)(H₂O)₄]²⁺ species (M = Mn^II, Ni^II, Zn^II) and [Mo₆O₁₉]^2- anions are held together via C-H···O hydrogen bonds to give a 3D supramolecular architecture. In <b>4</b>, two [Co(TMR4A)(H₂O)₂]²⁺ cations were linked by one [β-Mo₈O₂₆]^4- anion to produce an attractive molecular dimer. Remarkably, <b>1</b>-<b>4</b>, as recyclable heterogeneous catalysts, exhibit efficient catalytic oxidation desulfurization activities toward thioethers. Particularly, <b>1</b>, as a representative example, features selective catalytic oxidation for sulfur mustard simulant. Moreover, their electrochemical properties were also studied.