Names | |||
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Preferred IUPAC name N,N,N-Trimethylmethanaminium [1] | |||
Other names | |||
Identifiers | |||
3D model (JSmol) | |||
ChEBI | |||
ChemSpider | |||
PubChem CID | |||
UNII | |||
CompTox Dashboard (EPA) | |||
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Properties | |||
C4H12N+ | |||
Molar mass | 74.14 g/mol | ||
Related compounds | |||
Related isoelectronic | neo-pentane | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Tetramethylammonium (TMA) is the simplest quaternary ammonium cation. It has the chemical formula [Me4N]+ and consists of four methyl groups (−CH3, denoted Me) attached to a central nitrogen atom. The cation is isoelectronic with neopentane (Me4C). It is positively-charged and can only be isolated in association with a counter-ion. Common salts include tetramethylammonium chloride and tetramethylammonium hydroxide. Tetramethylammonium salts are used in chemical synthesis and in pharmacological research. It confers no color to its salts.
In the toxicological literature, naturally occurring tetramethylammonium (anion unspecified) is often referred to by the name "tetramine". Unfortunately, this non-systematic or "trivial" name is also used for other chemical entities, including a toxic rodenticide (Tetramethylenedisulfotetramine). Similarly, the acronym "TMA", which is frequently used for tetramethylammonium in the pharmacological literature, may also refer to the investigational drug 3,4,5-trimethoxyamphetamine, which, being a close structural analog of mescaline, has been the subject of numerous publications.
TMA has been detected in or isolated from a number of marine organisms, mostly amongst the Cnidaria and Mollusca, notably in some species of Neptunea (commonly called whelks) that are eaten by humans. [2] [3] It has also been found in one plant, the African Courbonia virgata (Cappariaceae). [4] TMA also occurs within the crystal structure Tsaregorodtsevite, a rare Sodalite group mineral with the formula N(CH3)4AlSi5O12 found on Gora Yaruta Mountain, Khanty-Mansi Autonomous Okrug, Russia. [5]
Tetramethylammonium ion is typically prepared by the reaction between trimethylamine and a methyl chloride: [6]
[14C]-labeled TMA has been made by this method. [7]
Although this reaction is suitable for the common halides, tetramethylammonium salts with more complex anions may be prepared by salt metathesis reactions, e.g. tetramethylammonium borohydride has been made from tetramethylammonium hydroxide as shown: [8]
Although TMA salts do possess some of the phase-transfer catalytic properties that are characteristic of quaternary ammonium compounds, they tend to behave atypically because of the relatively high hydrophilicity of the TMA cation. [9]
TMA cation is hydrophilic. [10] The octanol-water partition coefficient of TMA iodide, Po-w, is 1.2×10−4 (or log P ≈ −3.92). [7]
In the TMA cation, the methyl groups are tetrahedrally arranged around the central N atom, as is evident from X-ray crystallographic studies of various of its salts. [11] [12] From measurements taken on molecular models, it has been estimated that the diameter of the TMA ion is ~0.6 nm; [13] From more accurate physico-chemical measurements, the ionic radius for TMA is given as 0.322 nm; several thermodynamic parameters for the TMA ion are also recorded. [14] [15] The paper by Aue et al. gives a good discussion of the methods by which the ionic radius was determined. [14]
The pharmacological literature on tetramethylammonium is extensive. [16] In general, TMA is a cholinomimetic whose effects mimic most of those produced by exogenous acetylcholine. [17]
Pharmacological experiments with TMA have been performed using one of its salts, typically the chloride, bromide or iodide, since these anions were not expected to interfere with the actions of the TMA cation. In the early pharmacological literature, however, there are references to the use of "tetramethylammonium hydroxide" or "tetramethylammonium hydrate", which were meant to facilitate comparison between weight-based dosages of different TMA salts, [18] but did not involve the actual use of tetramethylammonium hydroxide, whose strong basicity would have been incompatible with physiological conditions. [2]
A thorough review of the pharmacology of TMA from a toxicological perspective, and current up to 1989, has been given by Anthoni and co-workers. [2] Thus, the effects of TMA on nicotinic and muscarinic ACh receptors first stimulate, then block neurotransmission in sympathetic and parasympathetic ganglia, with depolarization. TMA also acts as an agonist at muscarinic receptors in post-ganglionic nerve endings in smooth muscles, cardiac muscle, and exocrine glands. In skeletal muscle, TMA initially causes fasciculations, then paralysis, as a result of the depolarization from stimulation of nicotinic ACh receptors.
Absorption: TMA is readily absorbed from the gastro-intestinal tract. [2] Studies on the rat jejunum indicated that TMA absorption involved a combination of simple diffusion and carrier-mediated transport, with nearly 100% absorption occurring within 60 to 90 minutes. By comparison, tetraethylammonium and tetrapropylammonium ions were only absorbed to the extent of ~30%. [19]
Distribution: Intraperitoneal administration of radio-labeled tetramethylammonium iodide to mice showed that TMA was rapidly distributed to all parts of the body, with the highest concentrations being in the kidney and liver. [7] Similar results were reported by Neef and co-workers using rats. [20]
Metabolism and excretion: Parenteral administration of radio-labeled tetramethylammonium iodide to rats resulted in almost the whole dose being excreted in urine, without any evidence of metabolic transformation. [20]
The human toxicology of TMA (under the name "tetramine") has been studied primarily in the context of accidental poisoning after ingestion of Neptunea species. [2] Symptoms include the following: nausea, vomiting, headache, vertigo/dizziness, impaired vision/temporary blindness, diplopia, photophobia, lack of balance, feeling of intoxication and urticaria. These symptoms appear within 30 minutes but recovery is usually complete after a few hours. Only one account of human death following ingestion of TMA (from the plant Courbonia virgata) has been recorded. [4] Although many of these symptoms can be accounted for on the basis of impairment of neurotransmission in the autonomic nervous system, there also seem to be distinct indications of central affects. [2]
In animal studies, parenteral administration of TMA-containing extracts from Neptunea to mice, cats and fish mainly show effects involving skeletal muscles: there are muscular fasciculations, convulsions, loss of balance, motor paralysis and ultimately cessation of respiration. [2]
The lethal oral dose of TMA for humans has been estimated at 3–4 mg/kg. [2] [4] The lethal dose for rats was estimated to be ~45–50 mg/kg, p.o., and ~15 mg/kg, i.p. [21]
LD50 for TMA chloride: 25 mg/kg (mouse, i.p.); 40 mg/kg (mouse, s.c.). LC50 for TMA chloride: 462 mg/L for 96 hrs. (Fathead minnow, Pimephales promelas). [22] [23]
Erbium is a chemical element; it has symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare-earth element, originally found in the gadolinite mine in Ytterby, Sweden, which is the source of the element's name.
Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) molecular ion with the chemical formula NH+4 or [NH4]+. It is formed by the addition of a proton to ammonia. Ammonium is also a general name for positively charged (protonated) substituted amines and quaternary ammonium cations, where one or more hydrogen atoms are replaced by organic or other groups. Not only is ammonium a source of nitrogen and a key metabolite for many living organisms, but it is an integral part of the global nitrogen cycle. As such, human impact in recent years could have an effect on the biological communities that depend on it.
Fluoride is an inorganic, monatomic anion of fluorine, with the chemical formula F−
, whose salts are typically white or colorless. Fluoride salts typically have distinctive bitter tastes, and are odorless. Its salts and minerals are important chemical reagents and industrial chemicals, mainly used in the production of hydrogen fluoride for fluorocarbons. Fluoride is classified as a weak base since it only partially associates in solution, but concentrated fluoride is corrosive and can attack the skin.
Tetraethylammonium (TEA) is a quaternary ammonium cation with the chemical formula [Et4N]+, consisting of four ethyl groups attached to a central nitrogen atom. It is a counterion used in the research laboratory to prepare lipophilic salts of inorganic anions. It is used similarly to tetrabutylammonium, the difference being that its salts are less lipophilic, more easily crystallized and more toxic.
Neodymium(III) chloride or neodymium trichloride is a chemical compound of neodymium and chlorine with the formula NdCl3. This anhydrous compound is a mauve-colored solid that rapidly absorbs water on exposure to air to form a purple-colored hexahydrate, NdCl3·6H2O. Neodymium(III) chloride is produced from minerals monazite and bastnäsite using a complex multistage extraction process. The chloride has several important applications as an intermediate chemical for production of neodymium metal and neodymium-based lasers and optical fibers. Other applications include a catalyst in organic synthesis and in decomposition of waste water contamination, corrosion protection of aluminium and its alloys, and fluorescent labeling of organic molecules (DNA).
In organic chemistry, quaternary ammonium cations, also known as quats, are positively-charged polyatomic ions of the structure [NR4]+, where R is an alkyl group, an aryl group or organyl group. Unlike the ammonium ion and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged, independent of the pH of their solution. Quaternary ammonium salts or quaternary ammonium compounds are salts of quaternary ammonium cations. Polyquats are a variety of engineered polymer forms which provide multiple quat molecules within a larger molecule.
In chemistry, the term phosphonium describes polyatomic cations with the chemical formula PR+
4. These cations have tetrahedral structures. The salts are generally colorless or take the color of the anions.
In organic chemistry, an iminium cation is a polyatomic ion with the general structure [R1R2C=NR3R4]+. They are common in synthetic chemistry and biology.
In chemistry, a phase-transfer catalyst or PTC is a catalyst that facilitates the transition of a reactant from one phase into another phase where reaction occurs. Phase-transfer catalysis is a special form of catalysis and can act through homogeneous catalysis or heterogeneous catalysis methods depending on the catalyst used. Ionic reactants are often soluble in an aqueous phase but insoluble in an organic phase in the absence of the phase-transfer catalyst. The catalyst functions like a detergent for solubilizing the salts into the organic phase. Phase-transfer catalysis refers to the acceleration of the reaction upon the addition of the phase-transfer catalyst.
Tetramethylammonium hydroxide (TMAH or TMAOH) is a quaternary ammonium salt with molecular formula N(CH3)4+ OH−. It is commonly encountered in form of concentrated solutions in water or methanol. TMAH in solid state and its aqueous solutions are all colorless, but may be yellowish if impure. Although TMAH has virtually no odor when pure, samples often have a strong fishy smell due to presence of trimethylamine which is a common impurity. TMAH has several diverse industrial and research applications.
Molten salt is salt which is solid at standard temperature and pressure but liquified due to elevated temperature. A salt that is liquid even at standard temperature and pressure is usually called a room-temperature ionic liquid, and molten salts are technically a class of ionic liquids.
Dequalinium is a quaternary ammonium cation and bolaamphiphile commonly available as the dichloride salt. It is useful as an antiseptic and disinfectant. The bromide, iodide, acetate, and undecenoate salts are known as well. Dequalinium chloride is the active ingredient of several medications.
Tetraethylammonium bromide (TEAB) is a quaternary ammonium compound with the chemical formula C8H20N+Br−, often written as "Et4N+Br−" in the chemical literature. It has been used as the source of tetraethylammonium ions in pharmacological and physiological studies, but is also used in organic chemical synthesis.
Tetramethylammonium chloride is one of the simplest quaternary ammonium salts, with four methyl groups tetrahedrally attached to the central N. The chemical formula (CH3)4N+Cl− is often abbreviated further as Me4N+Cl−. It is a hygroscopic colourless solid that is soluble in water and polar organic solvents. Tetramethylammonium chloride is a major industrial chemical, being used widely as a chemical reagent and also as a low-residue bactericide in such processes as hydrofracking. In the laboratory, it has fewer synthetic chemical applications than quaternary ammonium salts containing longer N-alkyl substituents, which are used extensively as phase-transfer catalysts.
Neptunea antiqua, common name the red whelk, is a species of Northeast Atlantic sea snail, a marine gastropod mollusk in the family Buccinidae, the true whelks.
Neptunea arthritica is a species of sea snail, a marine gastropod mollusk in the family Buccinidae, the true whelks.
Candicine is a naturally occurring organic compound that is a quaternary ammonium salt with a phenethylamine skeleton. It is the N,N,N-trimethyl derivative of the well-known biogenic amine tyramine, and, being a natural product with a positively charged nitrogen atom in its molecular structure, it is classed as an alkaloid. Although it is found in a variety of plants, including barley, its properties have not been extensively studied with modern techniques. Candicine is toxic after parenteral administration, producing symptoms of neuromuscular blockade; further details are given in the "Pharmacology" section below.
Tetraethylammonium chloride (TEAC) is a quaternary ammonium compound with the chemical formula [N(CH2CH3)4]+Cl−, sometimes written as [NEt4]Cl. In appearance, it is a hygroscopic, colorless, crystalline solid. It has been used as the source of tetraethylammonium ions in pharmacological and physiological studies, but is also used in organic chemical synthesis.
Tetraethylammonium iodide is a quaternary ammonium compound with the chemical formula C8H20N+I−. It has been used as the source of tetraethylammonium ions in pharmacological and physiological studies, but is also used in organic chemical synthesis.