Sodium tetracarbonyl ferrate

Structural formula
General
Surname	Sodium tetracarbonyl ferrate
other names	Collman's reagent
Molecular formula	Na 2 [Fe (CO) 4 ]
Brief description	white solid
External identifiers / databases
CAS number 14878-31-0 EC number 238-951-0 ECHA InfoCard 100.035.395 Wikidata Q3271014
properties
Molar mass	213.87 g mol −1
Physical state	firmly
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Sodium tetracarbonyl ferrate (II) is an inorganic compound with the formula Na ₂ [Fe (CO) ₄ ]. It is an air-sensitive, colorless solid, the tetrahydrofuran adduct of which is used in organic chemistry under the name of Collman's reagent for the synthesis of aldehydes from alkyl bromides . Collman called the compound the transition metal equivalent to Grignard compounds .

presentation

Sodium tetracarbonyl ferrate (II) can be obtained by reducing iron pentacarbonyl with sodium dissolved in liquid ammonia .

${\displaystyle \mathrm {[Fe(CO)_{5}]+2\ Na\rightarrow \ Na_{2}[Fe(CO)_{4}]+CO} }$

Alternatively, sodium amalgam in tetrahydrofuran can be used as a reducing agent. With this method, the resulting complex can be converted directly into the further reaction steps in a one-pot reaction .

use

The compound can be used to convert primary alkyl bromides into the corresponding aldehydes. In the first step, the alkyl complex is formed with the formation of sodium bromide .

${\displaystyle \mathrm {Na_{2}[Fe(CO)_{4}]+RBr\ \rightarrow \ Na[Fe(R)(CO)_{4}]+NaBr} }$

The aldehyde is released by adding triphenylphosphine and then acidifying it with acetic acid .

${\displaystyle \mathrm {Na[Fe(R)(CO)_{4}]+PPh_{3}\ \rightarrow \ Na[Fe(C(=O)R)(CO)_{3}(PPh_{3})]} }$

The resulting primary alkyl complex can be converted into the acyl complex by triphenylphosphine and into the carboxylic acid by oxidation with oxygen and subsequent acidification . The acyl complex is converted into the carboxylic acid chlorides by oxidation with halogens .

If, instead of alkyl bromides, acid chlorides are reacted with sodium tetracarbonyl ferrate, the resulting acyl complexes release the aldehyde through reaction with mineral acids.

Individual evidence

1. ↑ Entry on Collman's reagent. In: Römpp Online . Georg Thieme Verlag, accessed on Dec 14, 2015.
2. ^ ^{A b} Robert J. Angelici: Inorganic Syntheses, Reagents for Transition Metal Complex and ... John Wiley & Sons, 2009, ISBN 0-470-13294-9 , pp. 206 ( limited preview in Google Book search).
3. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
4. ↑ James P. Collman: Disodium tetracarbonylferrate, a transition metal analog of a Grignard reagent. In: Accounts of Chemical Research. 8, 1975, pp. 342-347, doi : 10.1021 / ar50094a004 .
5. ↑ H. Behrens, R. Weber: On the knowledge of the chemistry of metal carbonyls in liquid ammonia. I. About the reactions of the carbonyls of iron and cobalt with alkali metals. In: Journal of Inorganic and General Chemistry. 281, 1955, pp. 190-198, doi : 10.1002 / zaac.19552810309 .
6. ↑ Manning P. Cooke: Facile conversion of alkyl bromides into aldehydes using sodium tetracarbonylferrate (-II). In: Journal of the American Chemical Society. 92, 1970, pp. 6080-6082, doi : 10.1021 / ja00723a056 .

literature

Encyclopedia of Reagents for Organic Synthesis , 1999–2013, John Wiley and Sons, Inc., entry for Disodium Tetracarbonylferrate (II)