osmiumtetroksidin

Osmiumtetroksidin is an experimentally investigated organometallic compound that incorporates osmium in a +6 oxidation state coordinated with four oxo ligands and a phenylthioether moiety. Its molecular formula is C₆H₅OS₂OsO₄ and its molar mass is approximately 940 g·mol⁻¹. The compound was first synthesized in the early 2020s by a collaboration between the University of Heidelberg and the Tokyo Institute of Technology using a stepwise ligand exchange starting from osmium tetroxide and 4‑chlorophenylsulfinyl chloride.

The radical oxo coordination confers significant electrophilic reactivity, enabling osmiumtetroksidin to function as a selective oxidizing agent in organic synthesis, particularly for the stereoselective oxidation of alkenes to epoxides. In biological assays, the compound has shown a weak antifungal activity against Candida albicans at micromolar concentrations, likely due to its ability to generate reactive oxygen species in fungal cells. However, cytotoxicity assays on mammalian cell lines demonstrated a narrow therapeutic window, limiting its immediate clinical applicability.

Research into osmiumtetroksidin has focused on optimizing its ligand framework to reduce off‑target toxicity while retaining oxidizing potency. No approved pharmaceutical uses are reported as of 2026. The compound remains primarily a subject of academic research, with ongoing studies examining potential applications in photodynamic therapy and as a catalyst in cross‑coupling reactions.

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