Dimanganese decacarbonyl
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| Dimanganese decacarbonyl | |
|---|---|
| Image:Dimanganese decacarbonyl.jpg | |
| General | |
| Systematic name | Dimanganese decacarbonyl |
| Other names | Manganese carbonyl Decacarbonyldimanganese |
| Molecular formula | Mn2CO10 |
| Molar mass | 389.98 g/mol |
| Appearance | yellow crystals |
| CAS number | [10170-69-1] |
| Properties | |
| Density and phase | 1.750 g/cm3 |
| Solubility in water | insoluble |
| Other solvents | ca. 300 g/L in toluene THF |
| Melting point | 154 °C |
| Boiling point | sublimes 60 °C (0.5 mm Hg) |
| Structure | |
| Dipole moment | 0 D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | CO source |
| R/S statement | R: 23/24/25 S: 22-26-36/37/39-45 |
| RTECS number | GG0300000 |
| Related compounds | |
| Related compounds | Co2(CO)8 Fe3(CO)12 Fe2(CO)9 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Dimanganese decacarbonyl is the chemical compound Mn2(CO)10. This metal carbonyl is an important reagent in the organometallic chemistry of manganese.[1] Whilst many metal carbonyls have been exploited in organic synthesis, this compound has more limited applications.
Contents |
[edit] Synthesis
The compound was first prepared in low yield by the reduction of manganese iodide with magnesium under CO.[2] A more efficient preparation is conducted by reduction of anhydrous MnCl2 with sodium benzophenone ketyl under 200 atmospheres of CO.[3] The availability of inexpensive Methylcyclopentadienyl manganese tricarbonyl ("MMT") has led to a low pressure route to Mn2(CO)10.[4]
[edit] Structure
Mn2(CO)10 has no bridging CO ligands: it can be described (CO)5Mn-Mn(CO)5. There are two kinds of CO ligands; one CO on each Mn is coaxial with the Mn-Mn bond, and four on each manganese that are perpendicular to it (equatorial). In the stable rotamer, the two Mn(CO)5 subunits are staggered. The overall molecule thus belongs to the point group D4d, which is an uncommon symmetry.
[edit] Reactions
Mn2(CO)10 is quite air stable as a crystalline solid but solutions should be handled using Schlenk techniques. It finds limited use in organic synthesis.[5] Characteristic reactions:
- Reduction of Mn2(CO)10 gives the manganese pentacarbonyl anion, which can be isolated as a salt:
- Mn2(CO)10 + 2 Na → 2 Na[Mn(CO)5]
This anion is a versatile nucleophile. Protonation gives the hydride [HMn(CO)5], and methylation gives [(CH3)Mn(CO)5].
- Halogenation of Mn2(CO)10proceeds with scission of the Mn-Mn bonds.
- Mn2(CO)10 + Br2 → 2[Mn(CO)5Br]
[edit] Safety
Mn2(CO)10 is a volatile source of a metal and a source of CO.
[edit] References
- ^ Elschenbroich, C.; Salzer, A. ”Organometallics : A Concise Introduction” (2nd Ed) (1992) Wiley-VCH: Weinheim. ISBN 3-527-28165-7
- ^ Brimm, E. O.; Lynch, M. A.; Sesny, W. J. "Preparation and Properties of Manganese Carbonyl" Journal of the American Chemical Society 1954, volume 76, page 3831 - 3835.
- ^ King, R. B. Organometallic Syntheses. Volume 1 Transition-Metal Compounds; Academic Press: New York, 1965. ISBN 0-444-42607-8
- ^ King, R. B.; Stokes, J. C.; Korenowski, T. F. "A Convenient Synthesis of Dimanganese Decarbonyl from Inexpensive Starting Materials at Atmospheric Pressure" Journal of Organometallic Chemistry 1968, volume 11, Pages 641-643.
- ^ Pauson, P. L. “Decacarbonyldimanganese” in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
