My watch list
my.chemeurope.com  
Login  

Diiron nonacarbonyl



Diiron nonacarbonyl
IUPAC name Diiron nonacarbonyl
Other names Iron enneacarbonyl
Identifiers
CAS number 15321-51-4
Properties
Molecular formula Fe2CO9
Molar mass 363.78 g/mol
Appearance orange crystals
Density 2.85 g/cm3
Melting point

decomposes at 100 °C

Boiling point

decomposes

Solubility in water insoluble
Structure
Dipole moment 0 D
Hazards
Main hazards CO source
R-phrases 11-23/25
S-phrases 16-28-36/37/39-45
Related Compounds
Related compounds Fe(CO)5
Fe3(CO)12
Mn2(CO)10
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Diiron nonacarbonyl (referred to as diiron enneacarbonyl in the older literature) is the chemical compound with the formula Fe2(CO)9. This metal carbonyl is an important reagent in organometallic chemistry and of occasional use in organic synthesis.[1] It is a more reactive source of Fe(0) than Fe(CO)5 and less dangerous to handle because it is nonvolatile. One of the strangest properties of this micaceous, orange solid is that it is virtually insoluble in all known solvents.

Contents

Synthesis

Photolysis of Fe(CO)5, typically in acetic acid solution, produces Fe2(CO)9 in good yield:[2]

2 Fe(CO)5 → Fe2(CO)9 + CO

Structure

Fe2(CO)9 consists of a pair of Fe(CO)3 centers linked by three bridging CO ligands. The iron atoms are equivalent and octahedral. Elucidation of the structure of Fe2(CO)9 has proven to be challenging because of its very low solubility, which prevents growth of crystals. The Mößbauer spectrum reveals one quadrupole doublet, consistent with the D3h-symmetric structure.

Reactions

Fe2(CO)9 is primarily employed as a precursor to compounds of the type Fe(CO)4L and Fe(CO)3(diene). Such syntheses are typically conducted in THF solution. In these conversions, it is proposed that small amounts of Fe2(CO)9 dissolve according the following reaction:

Fe2(CO)9 → Fe(CO)5 + Fe(CO)4(THF)

Cyclobutadieneiron tricarbonyl is prepared using Fe2(CO)9. Fe2(CO)9 has also been employed in the synthesis of cyclopentadienones via a net [2+3]-cycloaddition from dibromoketones.[3]

Safety

Fe2(CO)9 is a source of CO although it is nonvolatile and insoluble.

References

  1. ^ Elschenbroich, C.; Salzer, A. ”Organometallics : A Concise Introduction” (2nd Ed) (1992) Wiley-VCH: Weinheim. ISBN 3-527-28165-7
  2. ^ King, R. B. Organometallic Syntheses. Volume 1 Transition-Metal Compounds; Academic Press: New York, 1965. ISBN 0-444-42607-8
  3. ^ R. Noyori, R.; Yokoyama, K.; Hayakawa, Y. (1988). "Cyclopentanones from α, α'-Dibromoketones and Enamines: 2,5-Dimethyl-3-Phenyl-2-Cyclopenten-1-one". Org. Synth.; Coll. Vol. 6: 520. 
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Diiron_nonacarbonyl". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE