Osmium pentacarbonyl is the

organoosmium compound Organoruthenium chemistry is the chemistry of organometallic compounds containing a carbon to ruthenium chemical bond. Several organoruthenium catalysts are of commercial interest and organoruthenium compounds have been considered for cancer therapy ...

with the formula Os(CO)₅. It is the simplest isolatable

carbonyl complex Metal carbonyls are coordination complexes of transition metals with carbon monoxide ligands. Metal carbonyls are useful in organic synthesis and as catalysts or catalyst precursors in homogeneous catalysis, such as hydroformylation and Reppe ch ...

of osmium. Osmium pentacarbonyl is a colorless volatile liquid that is obtained by treating solid triosmium dodecacarbonyl under 200 atmospheres of carbon monoxide at 280-290 °C. In contrast, also at 200 atm of CO, solid Ru₃(CO)₁₂ converts to Ru(CO)₅ at milder temperature of 160 °C.

Reactions

Samples of Os(CO)₅ convert back to the trioosmium cluster upon heating to 80 °C. The analogous conversion of Ru(CO)₅ back to Ru₃(CO)₁₂ occurs at room temperature. Chlorination of the pentacarbonyl gives a cationic pentacarbonyl complex: :Os(CO)₅ + Cl₂ → s(CO)₅Clsup>+Cl⁻ Upon UV irradiation, hexane solutions of the pentacarbonyl react with ethylene to give mono-, di-, and trisubstituted derivatives: :Os(CO)₅ + nC₂H₄ → Os(CO)_5-n(C₂H₄)_n + nCO (n = 1,2,3)

References

{{Osmium compounds Organoosmium compounds Carbonyl complexes Osmium compounds