Osmium pentacarbonyl is the organoosmium compound with the formula Os(CO)5. It is the simplest isolatable carbonyl complex 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.[1]
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3D model (JSmol)
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| C5O5Os | |
| Molar mass | 330.28 g·mol−1 |
| Appearance | colorless liquid |
| Melting point | 2–2.5 °C (35.6–36.5 °F; 275.1–275.6 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Reactions
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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.[1] Chlorination of the pentacarbonyl gives a cationic pentacarbonyl complex:[1]
- Os(CO)5 + Cl2 → [Os(CO)5Cl]+Cl−
Upon UV irradiation, hexane solutions of the pentacarbonyl react with ethylene to give mono-, di-, and trisubstituted derivatives:[3]
- Os(CO)5 + n C2H4 → Os(CO)5-n(C2H4)n + n CO (n = 1,2,3)
References
edit- ^ a b c Rushman, Paul; Van Buuren, Gilbert N.; Shiralian, Mahmoud; Pomeroy, Roland K. (1983). "Properties of the Pentacarbonyls of Ruthenium and Osmium". Organometallics. 2 (5): 693–694. doi:10.1021/om00077a026.
- ^ Moss, John R.; Graham, William A. G. (1977). "The Enneacarbonyls of Ruthenium and Osmium". Journal of the Chemical Society, Dalton Transactions: 95. doi:10.1039/DT9770000095.
- ^ Kiel, Gong Yu; Takats, Josef; Grevels, Friedrich Wielhelm (1987). "Multisubstitution of Os(CO)5 by ethylene: Isomeric Os(CO)2(C2H4)3 and a Derivative of Os(CO)(C2H4)4". Journal of the American Chemical Society. 109 (7): 2227–2229. doi:10.1021/ja00241a075.