Cis-Dichlorobis(ethylenediamine)cobalt(III) chloride
Encyclopedia
cis-Dichlorobiscobalt(III) chloride is an organic compound
with formula [CoCl2(en)2]Cl (en = ethylenediamine). It is a violet diamagnetic solid that is soluble in water. One chloride ion in this salt readily undergoes ion exchange but the two other chlorides are less reactive, being bound to the metal center.
The initial product contains HCl, which is removed by heating. Alternatively, (carbonato)bis(ethylenediamine)cobalt (III) chloride reacts with hydrochloric acid at 10 °C to give the same species.
into two enantiomer
s (Λ and Δ) by the formation of the d-α-bromocamphor-π-sulfonate salt. The diastereomer
ic salts are separated by recrystallization. After their purification, the individual diastereomers are converted back to the chloride salt by reaction with ice cold hydrochloric acid.
) for the preparation of other cobalt salt complexes.
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with formula [CoCl2(en)2]Cl (en = ethylenediamine). It is a violet diamagnetic solid that is soluble in water. One chloride ion in this salt readily undergoes ion exchange but the two other chlorides are less reactive, being bound to the metal center.
Synthesis
Cis-Dichlorobis(ethylenediamine)cobalt(III) chloride is obtained by heating trans-[CoCl2(en)2]Cl e.g. using a steam bath. The trans isomer is in turn synthesized by the reaction of cobalt chloride and ethylenediamine in hydrochloric acid in the presence of oxygen:- 4 CoCl2 + 8 en + 4 HCl + O2 → 4 trans-[CoCl2(en)2]Cl + 2 H2O
The initial product contains HCl, which is removed by heating. Alternatively, (carbonato)bis(ethylenediamine)cobalt (III) chloride reacts with hydrochloric acid at 10 °C to give the same species.
- [Co(CO3)en2)]Cl + 2 HCl → trans-[CoCl2(en)2]Cl + CO2 + H2O
Optical resolution
The cis isomer is formed as a racemate, which can be resolvedChiral resolution
Chiral resolution in stereochemistry is a process for the separation of racemic compounds into their enantiomers. It is an important tool in the production of optically active drugs...
into two enantiomer
Enantiomer
In chemistry, an enantiomer is one of two stereoisomers that are mirror images of each other that are non-superposable , much as one's left and right hands are the same except for opposite orientation. It can be clearly understood if you try to place your hands one over the other without...
s (Λ and Δ) by the formation of the d-α-bromocamphor-π-sulfonate salt. The diastereomer
Diastereomer
Diastereomers are stereoisomers that are not enantiomers.Diastereomerism occurs when two or more stereoisomers of a compound have different configurations at one or more of the equivalent stereocenters and are not mirror images of each other.When two diastereoisomers differ from each other at...
ic salts are separated by recrystallization. After their purification, the individual diastereomers are converted back to the chloride salt by reaction with ice cold hydrochloric acid.
Comparison of cis and trans isomers
This salt is less soluble than the dull-green isomeric trans-Dichlorobis(ethylenediamine)cobalt(III) chloride (CAS#14040-33-6). This pair of isomers were significant in the development of the area of coordination chemistry. The chiral cis isomer can be obtained by heating the trans isomer. Both isomers of dichlorobis(ethylenediamine)cobalt(III) chloride have often used in stereochemical studies and as intermediates (like Tris(ethylenediamine)cobalt(III) chlorideTris(ethylenediamine)cobalt(III) chloride
Triscobalt chloride is a coordination complex with the formula [Co3]Cl3 . This complex was important in the history of coordination chemistry because of its stability and its stereochemistry. Many different salts have been described...
) for the preparation of other cobalt salt complexes.