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 |
| SMILES | ? |
| 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 pyrophoric |
| Flash point | ? °C |
| R/S statement | R: 23/24/25 S: 22-26-36/37/39-45 |
| RTECS number | GG0300000 |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| 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] Whereas 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 benzophenoneketyl under 200 atm 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 on each Mn that is coaxial with the Mn-Mn bond. The eight remaining CO ligands are equatorial. In the stable rotamer, the two Mn(CO)5 subunits are staggered. The overall molecule thus has the point group symmetrypoint group D4d, which is an uncommon symmetry. The significance of this structure is that the direct role of the metal-metal bond is obvious.
[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 anion:
- Mn2(CO)10 + 2 Na → 2 NaMn(CO)5
NaMn(CO)5 is a versatile nucleophile. Protonation gives the hydride HMn(CO)5, methylation gives CH3Mn(CO)5.
- Halogenation proceeds with scission of the Mn-Mn bonds.
- Mn2(CO)10 + Br2 → 2 2 BrMn(CO)5
[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.
