Synthesis of polyoxothiometalates through site-selective post-editing sulfurization of polyoxometalates

Abstract

Polyoxometalates (POMs) function as platforms for synthesizing structurally well-defined inorganic molecules with diverse structures, metals, compositions, and arrangements. Although post-editing of the oxygen sites of POMs has great potential for development of unprecedented structures, electronic states, properties, and applications, facile methods for site-selective substitution of the oxygen sites with other atoms remain limited. Herein, we report a direct site-selective oxygen–sulfur substitution method that enables transforming POMs [XW₁₂O₄₀]⁴⁻ (X = Si, Ge) to Keggin-type polyoxothiometalates (POTMs) [XW₁₂O₂₈S₁₂]⁴⁻ using sulfurizing reagents in an organic solvent. The resulting POTMs retain the original Keggin-type structure, with all 12 surface WO groups selectively converted to WS without sulfurization of other oxygen sites. These POTMs show high stability against water and O₂ in organic solvents and a drastic change in the electronic states and redox properties. The findings of this study represent a facile method for converting POMs to POTMs, leading to the development of their unique properties and applications in diverse fields, including (photo)catalysis, sensing, optics, electronics, energy conversion, and batteries.