Hexol
Encyclopedia
Hexol is a cobalt
compound that was first prepared by Alfred Werner
in 1914 and represented the first non-carbon-containing chiral
compound. The salt with the molecular formula of
[Co((OH)2Co(NH3)4)3](SO4)3 was prepared starting from cobalt(II) sulfate
.
Optical resolution
of this compound was possible by treating the hexol chloride salt with the resolving agent
silver D-(+)-bromocamphor
sulphonate in dilute acetic acid. The D-hexol salt precipitated out from solution and the filtrate contained the L-hexol species. (D-hexol and L-hexol are enantiomer
s of each other; see here for D/L notation.)
Werner also published a second achiral hexol (a minor byproduct from the production of Fremy's salt
) that he incorrectly identified as a linear trimer.
In 2004 the second hexol was reinvestigated and found to be a hexanuclear species.
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....
compound that was first prepared by Alfred Werner
Alfred Werner
Alfred Werner was a Swiss chemist who was a student at ETH Zurich and a professor at the University of Zurich. He won the Nobel Prize in Chemistry in 1913 for proposing the octahedral configuration of transition metal complexes. Werner developed the basis for modern coordination chemistry...
in 1914 and represented the first non-carbon-containing chiral
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....
compound. The salt with the molecular formula of
[Co((OH)2Co(NH3)4)3](SO4)3 was prepared starting from cobalt(II) sulfate
Cobalt(II) sulfate
Cobalt sulfate is the inorganic compound with the formula CoSO4. It is the divalent cobalt salt of sulfuric acid. The most common form of cobalt sulfate are the hydrates CoSO4.7H2O and CoSO4.H2O...
.
Optical resolution
Chiral 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...
of this compound was possible by treating the hexol chloride salt with the resolving agent
Chiral Derivitizing Agent
A chiral derivatizing agent also known as a chiral resolving reagent, is a chiral auxiliary which can convert a mixture of enantiomers into diastereomers in order to analyse the quantities of each enantiomer present within the mix...
silver D-(+)-bromocamphor
Camphor
Camphor is a waxy, white or transparent solid with a strong, aromatic odor. It is a terpenoid with the chemical formula C10H16O. It is found in wood of the camphor laurel , a large evergreen tree found in Asia and also of Dryobalanops aromatica, a giant of the Bornean forests...
sulphonate in dilute acetic acid. The D-hexol salt precipitated out from solution and the filtrate contained the L-hexol species. (D-hexol and L-hexol are 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 of each other; see here for D/L notation.)
Werner also published a second achiral hexol (a minor byproduct from the production of Fremy's salt
Fremy's salt
Frémy's salt, discovered in 1845 by Edmond Frémy , is a chemical compound and a strong oxidizing agent. The formal name is disodium nitrosodisulfonate or Na2NO2, but the expression "Frémy's salt" refers equally well to potassium nitrosodisulfonate, also known as potassium peroxylamine disulfonate...
) that he incorrectly identified as a linear trimer.
In 2004 the second hexol was reinvestigated and found to be a hexanuclear species.
External links
- Hexol Molecule of the Month September 1997 Website
- National Pollutant Inventory - Cobalt fact sheet