Tungsten hexacarbonyl (also called tungsten carbonyl) is an organometallic compound with the formula W(CO)6. This complex gave rise to the first example of a dihydrogen complex.[2]
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| Names | |||
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| IUPAC name
Hexacarbonyltungsten
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| Other names
Tungsten carbonyl
Hexacarbonylwolfram | |||
| Identifiers | |||
3D model (JSmol)
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| ECHA InfoCard | 100.034.423 | ||
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |||
| C6O6W | |||
| Molar mass | 351.901 g/mol | ||
| Appearance | Colorless solid | ||
| Density | 2.65 g/cm3 | ||
| Melting point | 170 °C (338 °F; 443 K) (decomposes) | ||
| insoluble | |||
| Solubility | sparingly in THF | ||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards
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Flammable, CO source | ||
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| NFPA 704 (fire diamond) | |||
| Safety data sheet (SDS) | External SDS | ||
| Related compounds | |||
Other cations
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Chromium hexacarbonyl Molybdenum hexacarbonyl | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Like its chromium and molybdenum analogs, this colorless compound is noteworthy as a volatile, air-stable derivative of tungsten in its zero oxidation state.
Preparation, properties, and structure
editLike many metal carbonyls, W(CO)6 is generally prepared by "reductive carbonylation", which involves the reduction of a metal halide with under an atmosphere of carbon monoxide. As described in a 2023 survey of methods "most cost-effective routes for the synthesis of group 6 hexacarbonyls are based on the reduction of the metal chlorides (CrCl3, MoCl5 or WCl6) with magnesium, zinc or aluminium powders... under CO pressures".[3] The compound is relatively air-stable. It is sparingly soluble in nonpolar organic solvents. Tungsten carbonyl is widely used in electron beam-induced deposition technique - it is easily vaporized and decomposed by the electron beam providing a convenient source of tungsten atoms.[4]
W(CO)6 adopts an octahedral geometry consisting of six rod-like CO ligands radiating from the central W atom with dipole moment 0 debye.
Reactivity
editAll reactions of W(CO)6 commence with displacement of some CO ligands in W(CO)6. W(CO)6 behaves similarly to the Mo(CO)6 but tends to form compounds that are kinetically more robust.
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Treatment of tungsten hexacarbonyl with sodium cyclopentadienide followed by oxidation of the resulting NaW(CO)3(C5H5) gives cyclopentadienyltungsten tricarbonyl dimer.[5]
One derivative is the dihydrogen complex W(CO)3[P(C6H11)3]2(H2).[2]
Three of these CO ligands can be displaced by acetonitrile.[6] W(CO)6 has been used to desulfurize organosulfur compounds and as a precursor to catalysts for alkene metathesis.
Safety and handling
editLike all metal carbonyls, W(CO)6 is a dangerous source of volatile metal as well as CO.
References
edit- ^ Even, J.; Yakushev, A.; Dullmann, C. E.; Haba, H.; Asai, M.; Sato, T. K.; Brand, H.; Di Nitto, A.; Eichler, R.; Fan, F. L.; Hartmann, W.; Huang, M.; Jager, E.; Kaji, D.; Kanaya, J.; Kaneya, Y.; Khuyagbaatar, J.; Kindler, B.; Kratz, J. V.; Krier, J.; Kudou, Y.; Kurz, N.; Lommel, B.; Miyashita, S.; Morimoto, K.; Morita, K.; Murakami, M.; Nagame, Y.; Nitsche, H.; et al. (2014). "Synthesis and detection of a seaborgium carbonyl complex". Science. 345 (6203): 1491–3. Bibcode:2014Sci...345.1491E. doi:10.1126/science.1255720. PMID 25237098. S2CID 206558746. (subscription required)
- ^ a b Kubas, G. J., Metal Dihydrogen and σ-Bond Complexes, Kluwer Academic/Plenum Publishers: New York, 2001
- ^ Bruno, Sofia M.; Valente, Anabela A.; Gonçalves, Isabel S.; Pillinger, Martyn (2023). "Group 6 Carbonyl Complexes of N,O,P-Ligands as Precursors of High-Valent Metal-Oxo Catalysts for Olefin Epoxidation". Coordination Chemistry Reviews. 478: 214983. doi:10.1016/j.ccr.2022.214983. hdl:10773/40120. S2CID 255329673.
- ^ Randolph, S.; Fowlkes, J.; Rack, P. (2006). "Focused, Nanoscale Electron-Beam-Induced Deposition and Etching". Critical Reviews of Solid State and Materials Sciences. 31 (3): 55. Bibcode:2006CRSSM..31...55R. doi:10.1080/10408430600930438. S2CID 93769658.
- ^ Manning, A. R.; Hacket, Paul; Birdwhistell, Ralph (1990). Hexacarbonylbis(η5-Cyclopentadienyl)Dichromium, Molybdenum, and Tungsten and their Analogs, M2(η5-C5H4R)2(CO)6 (M = Cr, Mo, and W; R = H, Me or PhCH2). Inorganic Syntheses. Vol. 28. pp. 148–149. doi:10.1002/9780470132593.ch39. ISBN 978-0-470-13259-3.
- ^ Kubas, G. J.; van der Sluys, L. S. (1990). "TricarbonylTris(nitrile) Complexes of Cr, Mo, and W". Inorganic Syntheses. Vol. 28. pp. 29–33. doi:10.1002/9780470132593.ch6. ISBN 978-0-470-13259-3.