1-azanaphthalene-8-ol, Fennosan H 30, hydroxybenzopyridine, hoxybenzopyridine, oxychinolin, oxyquinoline, phenopyridine, quinophenol, oxine
3D model (JSmol)
|Molar mass||145.16 g/mol|
|Appearance||White crystalline needles|
|Melting point||76 °C (169 °F; 349 K)|
|Boiling point||276 °C (529 °F; 549 K)|
|G01AC30 (WHO) A01AB07 (WHO) D08AH03 (WHO) R02AA14 (WHO)|
|Safety data sheet||External MSDS|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
8-Hydroxyquinoline is an organic compound with the formula C9H7NO. It is a derivative of the heterocycle quinoline by placement of an OH group on carbon number 8. This light yellow compound is widely used commercially, although under a variety of names.
As a chelating agent
8-Hydroxyquinoline is a monoprotic bidentate chelating agent. In neutral solution, the hydroxyl is in the protonated form (pKa=9.89) and the nitrogen is not protonated (pKa=5.13). However, transient, a photochemically induced excited-state zwitterionic isomer exists in which H+ is transferred from the oxygen (giving an oxygen anion) to the nitrogen (giving a protonated nitrogen cation).
The complexes as well as the heterocycle itself exhibit antiseptic, disinfectant, and pesticide properties, functioning as a transcription inhibitor. Its solution in alcohol is used in liquid bandages. It once was of interest as an anti-cancer drug.
The reaction of 8-hydroxyquinoline with aluminium(III) results in Alq3, a common component of organic light-emitting diodes (OLEDs). Variations in the substituents on the quinoline rings affect its luminescence properties.
Related ligands include the Schiff bases derived from salicylaldehyde, such as salicylaldoxime, salen, and salicylaldehyde isonicotinoylhydrazone (SIH). 8-Mercaptoquinoline is the thiol analogue of 8-hydroxyquinoline.
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