Dimanganese decacarbonyl

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Dimanganese decacarbonyl
Dimanganese decacarbonyl
Dimanganese-decacarbonyl-3D-balls.png
Identifiers
CAS number 10170-69-1 YesY
PubChem 517769
ChemSpider 451751 YesY
RTECS number GG0300000
Jmol-3D images Image 1
Properties
Molecular formula C10O10Mn2
Molar mass 389.98 g/mol
Appearance yellow crystals
Density 1.750 g/cm3
Melting point 154 °C
Boiling point sublimes 60 °C
(0.5 mm Hg)
Solubility in water insoluble
Structure
Dipole moment 0 D
Hazards
R-phrases 23/24/25
S-phrases 22-26-36/37/39-45
Main hazards CO source
Related compounds
Related compounds Re2(CO)10
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 (77 °F), 100 kPa)
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Infobox references

Dimanganese decacarbonyl is the chemical compound with the formula Mn2(CO)10. This metal carbonyl is an important reagent in the organometallic chemistry of manganese.[1]

Synthesis[edit]

The compound was first prepared in low yield by the reduction of manganese iodide with magnesium under CO.[2] A more efficient preparation entails 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]

Structure[edit]

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 (293 pm), 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.[5]

Reactions[edit]

Mn2(CO)10 is air stable as a crystalline solid, but solutions require Schlenk techniques. It finds limited use in organic synthesis.[6] 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]

The anion is a versatile nucleophile. Protonation gives the hydride [HMn(CO)5], and methylation gives [(CH3)Mn(CO)5].

  • Halogenation of Mn2(CO)10 proceeds with scission of the Mn-Mn bond.
Mn2(CO)10 + Br2 → 2[Mn(CO)5Br]

Safety[edit]

Mn2(CO)10 is a volatile source of a metal and a source of CO.

References[edit]

  1. ^ Elschenbroich, C. "Organometallics" (2006) Wiley-VCH: Weinheim. ISBN 978-3-527-29390-2
  2. ^ 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.
  3. ^ King, R. B. Organometallic Syntheses. Volume 1 Transition-Metal Compounds; Academic Press: New York, 1965. ISBN 0-444-42607-8
  4. ^ 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.
  5. ^ L. F. Dahl, E. Ishishi, R. E. Rundle "Polynuclear Metal Carbonyls. I. Structures of Mn2(CO)10 and Re2(CO)10 J. Chem. Phys. 1957, volume 26, p. 1750. doi:10.1063/1.1743615
  6. ^ Pauson, P. L. "Decacarbonyldimanganese" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289.