rutheniumtetroxide

Ruthenium tetroxide, RuO4, is a volatile oxide of ruthenium in the +8 oxidation state. It is a powerful oxidant and is typically encountered as an in situ generated species rather than a isolable solid, because it rapidly decomposes in many environments. In its pure or concentrated form it appears as a violet or deep purple vapor or solution in organic solvents.

Preparation and handling of RuO4 rely on in situ generation from ruthenium sources under strongly oxidizing and acidic conditions. Common approaches involve oxidizing Ru(IV) oxides or Ru(III) salts with strong oxidants such as hot nitric or periodic acids. The compound is usually used immediately in catalytic or stoichiometric oxidations, and it is highly moisture- and temperature-sensitive, decomposing readily to lower-valent ruthenium oxides.

Properties of RuO4 include its high volatility, strong oxidizing power, and broad substrate scope. It readily oxidizes a wide range of organic substrates, including alkenes and alcohols, and can cleave alkenes to carbonyl-containing products or acids under appropriate conditions. Its oxidizing strength and volatility make it effective but difficult to handle, and it is typically employed in controlled, small-scale reactions.

Applications and significance in organic synthesis arise from its ability to effect difficult oxidations, including oxidative cleavage of alkenes and oxidation of alcohols. Because RuO4 is highly toxic and a strong oxidizer, its use is carefully regulated, and alternatives are often sought when feasible. Researchers date its history to early oxidation chemistry and continue to study catalytic systems that generate RuO4 in situ with reduced risk.

Safety and hazards: RuO4 is extremely toxic and a potent oxidizer. It is volatile and can cause severe respiratory and dermal harm. Handle only in appropriate facilities with strict inerting, ventilation, and protective equipment.