Tetraethylammonium ion

Structural formula of the tetraethylammonium ion

The tetraethylammonium ion is a monovalent cation with the empirical formula C ₈ H ₂₀ N ⁺ ( semi-structural formula (C ₂ H ₅ ) ₄ N ⁺ ). It consists of a nitrogen atom which is tetrahedrally surrounded by four ethyl residues and thus belongs to the group of quaternary ammonium compounds . Formally, it is derived from the ammonium ion by substituting the hydrogen atoms with ethyl radicals. The tetraethylammonium ion is one of the weakly coordinating cations . There are a large number of tetraethylammonium salts of the general formula C ₈ H ₂₀ NX, where X is a monovalent anion .

presentation

Tetraethylammonium salts can be prepared by reacting triethylamine with substituted ethyl compounds, the substituent being a leaving group , which then usually functions as a counterion of the salt.

${\displaystyle \mathrm {N(CH_{2}CH_{3})_{3}\ +\ CH_{3}CH_{2}X\longrightarrow \ N(CH_{2}CH_{3})_{4}X} }$

Reaction of triethylamine with ethyl iodide to form tetraethylammonium iodide .

However, the counterion can also be exchanged afterwards:

${\displaystyle \mathrm {N(CH_{2}CH_{3})_{4}Br\ +\ AgBF_{4}\longrightarrow \ N(CH_{2}CH_{3})_{4}BF_{4}\ +\ AgBr\downarrow } }$

Reaction of tetraethylammonium bromide with silver tetrafluoroborate to give tetraethylammonium tetrafluoroborate with precipitation of silver bromide .

use

It is a neurotoxin that u. a. used in neurophysiology to block the potassium channels in experiments on neurons . TEA blocks the voltage-activated potassium channels that are required for repolarization of the membrane potential after an action potential .

Salts

Tetraethylammonium forms salts with anions . Important ones include:

• Tetraethylammonium bromide
• Tetraethylammonium chloride
• Tetraethylammonium cyanide
• Tetraethylammonium hydroxide
• Tetraethylammonium iodide
• Tetraethylammonium nitrate
• Tetraethylammonium perfluorooctanesulfonate

literature

• Peter Deetjen: Physiology. 4th edition. Urban & Fischer, 2007, ISBN 978-3-437-44440-1 , p. 15. ( limited preview in Google book search)

Individual evidence

1. ^ KO Christe, WW Wilson: Reaction of the fluoride anion with acetonitrile. Chloroform and methylene chloride. In: J. Fluorine Chem. 47, 1990, pp. 117-120
2. ^ FM Menger, UV Venkataram: Proximity as a component of organic reactivity. In: J. Am. Chem. Soc. 107, 1985, pp. 4706-4709.
3. ↑ K. Fukui, K. Ohkubo, T. Yamabe: The Catalytic Activity of Onium Compounds in the Homogeneous Liquid Phase Oxidation of Cumene and α-Pinene. In: Bull. Chem. Soc. Jpn. 42, 1969, pp. 312-318.
4. ↑ B. Roux: Extracellular blockade of potassium channels by TEA +: the tip of the iceberg? In: J Gen Physiol . 128 (6), Dec 2006, pp. 649-657. PMID 17130517
5. ↑ External identifiers or database links for tetraethylammonium bromide : CAS number: 71-91-0, EC number: 200-769-4, ECHA InfoCard: 100.000.700 , GESTIS substance database : 492379 , PubChem : 6285 , ChemSpider : 6048 , Wikidata : Q5961420 .
6. ↑ External identifiers or database links for tetraethylammonium cyanide: CAS number: 13435-20-6, EC number: 236-566-2, ECHA InfoCard: 100.033.228 , Wikidata : Q83026984 .
7. ↑ External identifiers or database links for tetraethylammonium hydroxide: CAS number: 77-98-5, EC number: 201-073-3, ECHA InfoCard: 100.000.977 , GESTIS substance database : 492413 , PubChem : 6509 , ChemSpider : 6263 , Wikidata : Q27288030 .
8. ↑ External identifiers or database links for tetraethylammonium iodide: CAS number: 68-05-3, EC number: 200-676-9, ECHA InfoCard: 100.000.615 , PubChem : 6225 , ChemSpider : 5990 , Wikidata : Q7706337 .
9. ↑ External identifiers or database links for tetraethylammonium nitrate: CAS number: 1941-26-0, EC number: 217-725-5, ECHA InfoCard: 100.016.114 , Wikidata : Q72504985 .
10. ↑ External identifiers or database links for tetraethylammonium perfluorooctane sulfonate: CAS number: 56773-42-3, EC number: 260-375-3, ECHA InfoCard: 100.054.869 , GESTIS substance database : 146734 , PubChem : 92531 , ChemSpider : 83538 , Wikidata : Q72481197 .