8-Hydroxyquinoline (also known as oxine) is a
chelating agent
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...
which has been used for the
quantitative determination of metal ions.
In aqueous solution 8-hydroxyquinoline has a pK
a value of ca. 9.9 It reacts with metal ions, losing the proton and forming 8-hydroxyquinolinato-
chelate
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...
complexes.
The aluminium complex is a common component of
organic light-emitting diode
An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light ...
s (OLEDs). Variations in the substituents on the quinoline rings affect its
luminescence
Luminescence is spontaneous emission of light by a substance not resulting from heat; or "cold light".
It is thus a form of cold-body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions or stress on a crysta ...
properties.
In the photochemically induced excited-state
zwitterion
In chemistry, a zwitterion ( ; ), also called an inner salt or dipolar ion, is a molecule that contains an equal number of positively- and negatively-charged functional groups.
: With amino acids, for example, in solution a chemical equilibrium w ...
ic isomers are formed in which the hydrogen atom is transferred from oxygen to nitrogen.
The complexes as well as the heterocycle itself exhibit
antiseptic
An antiseptic (from Greek ἀντί ''anti'', "against" and σηπτικός ''sēptikos'', "putrefactive") is an antimicrobial substance or compound that is applied to living tissue/skin to reduce the possibility of infection, sepsis, or putre ...
,
disinfectant
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than s ...
, 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.
A thiol analogue,
8-mercaptoquinoline is also known.
The roots of the invasive plant ''
Centaurea diffusa
''Centaurea diffusa'', also known as diffuse knapweed, white knapweed or tumble knapweed, is a member of the genus ''Centaurea'' in the family Asteraceae. This species is common throughout western North America but is not actually native to the ...
'' release 8-hydroxyquinoline, which has a negative effect on plants that have not
co-evolved with it.
See also
*
Clioquinol, an antifungal drug and antiprotozoal drug.
*
PBT2
*
QUPIC
PB-22 (QUPIC, SGT-21 or 1-pentyl-1''H''-indole-3-carboxylic acid 8-quinolinyl ester) is a designer drug offered by online vendors as a cannabimimetic agent, and detected being sold in synthetic cannabis products in Japan in 2013. PB-22 represents ...
*
Ionophore
In chemistry, an ionophore () is a chemical species that reversibly binds ions. Many ionophores are lipid-soluble entities that transport ions across the cell membrane. Ionophores catalyze ion transport across hydrophobic membranes, such as ...
*
Trace metal detection test
References
{{DEFAULTSORT:Hydroxyquinoline, 8-
Antiseptics
Quinolinols