Description
Potassium osmate (VI) dehydrate is an inorganic compound with the formula H4K2O6Os. ISn the VI (6+) oxidation state the compound is a diamagnetic purple salt contains osmium. It is soluble in water and slowly decomposes in aqueous solution. Potassium osmate (VI) dehydrate is insoluble in ethereal and alcoholic solvents.
Preparation
Edmond Fremy first prepared potassium osmate (VI) dehydrate in 1844 by reducing perosmates using alcohol.
2OsO4 + C2H5OH + 3 KOH → CH3CO2K + 2 K2[OsO2(OH)4]
Applications and Reactions
Potassium osmate (VI) dehydrate is used as a catalyst in the dihydroxylation of cyclic internal alkenes such as lactams, 1,2 dioxines dihydrothiophenes and hexahydropyrans. The resulting diols from such reactions have been used in the preparation of various carbohydrate and similar molecular scaffolds. Potassium osmate (VI) dehydrate iss also used in the development of an asymmetric dihydroxylation methodology targeting heteroaromatic acrylates.
Chemical Properties
violet crystalline powder
Uses
Potassium osmium(VI) oxide dihydrate acts as a catalyst for the oxidative cleavage of olefins to ketones and carboxylic acids. It is employed in an intramolecular amidohydroxylation of carbamoyloxytethered olefins providing hydroxy oxazolidinones. It is also used as a reagent in the synthesis of amphidinolide B, which shows potent antitumor activity against human solid and blood tumor cells.
Uses
Determination of nitrogenous matter in water.
Reactivity Profile
catalyst for oxidative cleavage; oxidation reagent; used in dihydroxylation and aminohydroxylation reactions.
Hazard
Toxic by ingestion and inhalation.
storage
incompatible with strong oxidizing reagents. Toxic if inhaled. May cause respiratory tract irritation. Toxic if absorbed through the skin. Toxic if swallowed.
Structure and conformation
The complex anion is octahedral. Like related d2 dioxo complexes, the oxo ligands are trans. The Os=O and Os-OH distances are 1.75(2) and 1.99(2) Å, respectively. It is a relatively rare example of a metal oxo complex that obeys the 18e rule.
