8-Hydroxyquinoline (also known as oxine) is a
chelating agent 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 i ...
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 crys ...
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 wil ...
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, and pesticide properties, functioning as a
transcription inhibitor
Transcription is the process of copying a segment of DNA into RNA. The segments of DNA transcribed into RNA molecules that can encode proteins are said to produce messenger RNA (mRNA). Other segments of DNA are copied into RNA molecules called ...
. Its solution in alcohol is used in
liquid bandages. It once was of interest as an anti-cancer drug.
A thiol analogue,
8-mercaptoquinoline
8-Mercaptoquinoline is the organosulfur compound with the formula C9H7NSH. It is a derivative of the heterocycle quinoline, substituted in the 8-position with a thiol group. The compound is an analog of 8-hydroxyquinoline, a common chelating ag ...
is also known.
The roots of the invasive plant ''
Centaurea diffusa'' release 8-hydroxyquinoline, which has a negative effect on plants that have not
co-evolved with it.
See also
*
Clioquinol
Clioquinol (iodochlorhydroxyquin) is an antifungal drug and antiprotozoal drug. It is neurotoxic in large doses. It is a member of a family of drugs called hydroxyquinolines which inhibit certain enzymes related to DNA replication. The drugs h ...
, an antifungal drug and antiprotozoal drug.
*
PBT2
PBT2 is a safe-for-human-use Zinc ionophore and an experimental drug candidate. It is a second-generation 8-hydroxyquinoline analog intended to be a successor to clioquinol and a potential treatment of Alzheimer's disease and Huntington's disea ...
*
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 represen ...
*
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 liq ...
*
Trace metal detection test The trace metal detection test or technique was developed during the Vietnam War in the 1960s to identify people who may have been carrying firearms against their skin. A 0.2% solution of 8-hydroxyquinoline in isopropanol sprayed on the skin and ill ...
References
{{DEFAULTSORT:Hydroxyquinoline, 8-
Antiseptics
Quinolinols