Disodium tetracarbonylferrate
| Disodium tetracarbonylferrate | ||
|---|---|---|
 | ||
| IUPAC name disodium tetracarbonylferrate | ||
| Systematic name disodium tetracarbonylferrate | ||
| Other names disodium iron tetracarbonyl, Collman's reagent | ||
| Identifiers | ||
| CAS number | 14878-31-0 | |
| Properties | ||
| Molecular formula | C4FeNa2O4 | |
| Molar mass | 213.87 | |
| Appearance | Colorless solid | |
| Density | 2.16 g/cm3, solid | |
| Solubility in water | Decomposes | |
| Solubility | tetrahydrofuran, dimethylformamide, dioxane | |
| Structure | ||
| Crystal structure | Distorted tetrahedron | |
| Coordination geometry |
Tetrahedral | |
| Hazards | ||
| Main hazards | Pyrophoric | |
| Related compounds | ||
| Related compounds | Iron pentacarbonyl | |
 (verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| Infobox references | ||
Disodium tetracarbonylferrate is the chemical compound with the formula Na2[Fe(CO)4]. This oxygen-sensitive colourless solid is employed in organic synthesis,[1] mainly to synthesise aldehydes.[2] It is commonly used with dioxane complexed to the sodium cation, this dioxane solvate being known as Collman's reagent.[3] The tetracarbonylferrate dianion is tetrahedral.[4]
Synthesis
The reagent was reported by Cooke in 1970.[5] The current synthesis entails the reduction of a solution of iron pentacarbonyl in tetrahydrofuran by sodium naphthenide. The efficiency of the synthesis depends on the quality of the iron pentacarbonyl.[1]
Reactions
The reagent was originally described for the conversion of primary alkyl bromides, RBr, to the corresponding aldehydes in a two-step, "one-pot" reaction:[5]
- Na2[Fe(CO)4] + RBr → Na[RFe(CO)4] + NaBr
This solution is then treated sequentially with PPh3 and then acetic acid to give the aldehyde, RCHO.
Disodium tetracarbonylferrate can be used to convert acid chlorides to aldehydes. As for Cooke’s early discovery, an iron acyl complex undergoes protonolysis to give the aldehyde.
- Na2[Fe(CO)4] + RCOCl → Na[RC(O)Fe(CO)4] + NaCl
- Na[RC(O)Fe(CO)4] + HCl → RCHO + "Fe(CO)4" + NaCl
Disodium tetracarbonylferrate reacts with alkyl halides (RX) to produce alkyl complexes:
- Na2[Fe(CO)4] + RX → Na[RFe(CO)4] + NaX
Such iron alkyls can be converted to the corresponding carboxylic acid and acid halides:
- Na[RFe(CO)4] + O2, H+ →→ RCO2H + Fe...
- Na[RFe(CO)4] + X2 → RC(O)X + FeX2 + 3 CO + NaCl
One attraction of these methods is the low cost of the iron carbonyl as well as the fact that the procedures are relatively “green” because the side product is iron-based.
References
- ↑ 1.0 1.1 Strong, H.; Krusic, P. J.; San Filippo, J. (1990). "Sodium Carbonyl Ferrates, Na2[Fe(CO)4], Na2[Fe2(CO)8], and Na2[Fe3(CO)11]. Bis[μ-Nitrido-Bis(triphenylphosphorus)1+] Undeca-Carbonyltriferrate2-, [(Ph3P)2N]2[Fe3(CO)11]". In R. J. Angelici. Inorganic Syntheses (New York: J. Wiley & Sons) 28: 203–207. doi:10.1002/9780470132593.ch52. ISBN 0-471-52619-3.
- ↑ Pike, R. D. (2001). "Disodium Tetracarbonylferrate(-II)". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rd465.
- ↑ Miessler, G. L., Tarr, D. A. (2004). Inorganic Chemistry. Upper Saddle River, NJ: Pearson.
- ↑ Chin, H. B.; Bau, R. (1976). "The Crystal Structure of Disodium Tetracarbonylferrate. Distortion of the Tetracarbonylferrate2- Anion in the Solid State". Journal of the American Chemical Society 98 (9): 2434–2439. doi:10.1021/ja00425a009.
- ↑ 5.0 5.1 Cooke, M. P. (1970). "Facile Conversion of Alkyl Bromides into Aldehydes Using Sodium Tetracarbonylferrate(-II)". Journal of the American Chemical Society 92 (20): 6080–6082. doi:10.1021/ja00723a056.
Further reading
- Collman, J. P. (1975). "Disodium Tetracarbonylferrate, a Transition Metal Analog of a Grignard Reagent". Accounts of Chemical Research 8 (10): 342–347. doi:10.1021/ar50094a004.
- Ungurenasu, C.; Cotzur, C. (1982). "Disodium Tetracarbonylferrate: A Reagent for Acid Functionalization of Halogenated Polymers". Polymer Bulletin 6 (5–6): 299–303. doi:10.1007/BF00255401.
- Hieber, V. W.; Braun, G. (1959). Zeitschrift für Naturforschung B 14: 132.