Salicylaldoxime

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

<templatestyles src="Chembox/styles.css"/>

Template:Chembox image cellTemplate:Chembox AllOtherNamesTemplate:Chembox headerbarTemplate:Chembox IndexlistTemplate:Chembox JmolTemplate:Chembox ChEMBLTemplate:Chembox ECHATemplate:Chembox E numberTemplate:Chembox IUPHAR ligandTemplate:Chembox UNIITemplate:Chembox CompToxTemplate:Chembox headerbarTemplate:Chembox SolubilityInWaterTemplate:Chembox HazardsTemplate:Chembox Datapage checkTemplate:Yesno
Salicylaldoxime
Template:Longitem Template:Unbulleted list
ChEBI Template:Unbulleted list
ChemSpider Template:Unbulleted list
DrugBank Template:Unbulleted list
EC Number Template:Unbulleted list
KEGG Template:Unbulleted list
Template:Longitem Template:Unbulleted list
RTECS number Template:Unbulleted list
Script error: No such module "collapsible list".
Script error: No such module "collapsible list".
Template:Longitem Template:Chembox Elements/molecular formula
Molar mass Template:Chem molar mass
Appearance white to off-white crystals
Melting point Template:Chembox CalcTemperatures

Template:Chembox Footer/tracking container onlyScript error: No such module "TemplatePar".Template:Short description

Salicylaldoxime is an organic compound described by the formula C6H4CH=NOH-2-OH. It is the oxime of salicylaldehyde. This crystalline, colorless solid is a chelator and sometimes used in the analysis of samples containing transition metal ions, with which it often forms brightly coloured coordination complexes.[1]

Reactions

Salicylaldoxime is the conjugate acid of a bidentate ligand:

2 C6H4CH=NOH-2-OH + Cu2+ → Cu(C6H4CH=NOH-2-O)2 + 2 H+

In highly acidic media, the ligand protonates, and the metal aquo complex and aldoxime are liberated. In this way the ligand is used as a recyclable extractant. It typically forms charge-neutral complexes with divalent metal ions.

Analytical chemistry

File:Cu(Salox)2.png
Structure of the copper(II) complex of the conjugate base of salicylaldoxime. The hydroxyl groups form hydrogen bonds to the phenolate oxygens.

In the era when metals were analysed by spectrophotometry, many chelating ligands were developed that selectively formed brightly coloured complexes with particular metal ions. This methodology has been eclipsed with the introduction of inductively coupled plasma methodology. Salicylaldoxime can be used to selectively precipitate metal ions for gravimetric determination. It forms a greenish-yellow precipitate with copper at a pH of 2.6 in the presence of acetic acid. Under these conditions, this is the only metal that precipitates; at pH 3.3, nickel also precipitates. Iron (III) will interfere. [2] It has been used as an ionophore in ion selective electrodes, with good response to Pb2+ and Ni2+.[3]

Extraction of metals

Saloximes are used in the extraction and separation of metals from their ores. In one application of hydrometallurgy, Cu2+ is extracted into organic solvents as its saloxime complex.[4]

References

  1. Smith, Andrew G.; Tasker, Peter A.; White, David J. "The structures of phenolic oximes and their complexes" Coordination Chemistry Reviews 2003, volume24, pp. 61-85. Script error: No such module "CS1 identifiers".
  2. Script error: No such module "Citation/CS1".
  3. Script error: No such module "Citation/CS1".
  4. Script error: No such module "Citation/CS1".

External links