Last updated
Preferred IUPAC name
Other names
  • 2,2′,2′′-Nitrilotriethylamine
  • 2,2′,2′′-Triaminotriethylamine
  • TAEA
3D model (JSmol)
ECHA InfoCard 100.021.689 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 223-857-4
MeSH Tris(2-aminoethyl)amine
PubChem CID
RTECS number
  • KH8587082
UN number 2922
  • InChI=1S/C6H18N4/c7-1-4-10(5-2-8)6-3-9/h1-9H2 X mark.svgN
Molar mass 146.238 g·mol−1
AppearanceColorless liquid
Odor Ichtyal, ammoniacal
Density 0.976 g/mL (20 °C) [1]
Melting point −16 °C (3 °F; 257 K)
Boiling point 265 °C (509 °F; 538 K)
log P −2.664
Vapor pressure 3 Pa (at 20 °C)
1.497 [1]
−74.3–−72.9 kJ mol−1
−4860.6–−4859.2 kJ mol−1
GHS labelling:
GHS-pictogram-acid.svg GHS-pictogram-skull.svg
H301, H310, H314
P280, P302+P350, P305+P351+P338, P310
Flash point 113 °C (235 °F; 386 K)
Lethal dose or concentration (LD, LC):
  • 117 mg kg−1 (dermal, rabbit)
  • 246 mg kg−1 (oral, rat)
Safety data sheet (SDS)
Related compounds
Related amines
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Tris(2-aminoethyl)amine is the organic compound with the formula N(CH2CH2NH2)3. This colourless liquid is soluble in water and is highly basic, consisting of a tertiary amine center and three pendant primary amine groups. Abbreviated tren or TREN it is a crosslinking agent in the synthesis of polyimine networks and a tripodal ligand in coordination chemistry.


Tren is a C3-symmetric, tetradentate chelating ligand that forms stable complexes with transition metals, especially those in the 2+ and 3+ oxidation states. Tren complexes exist with relatively few isomers, reflecting the constrained connectivity of this tetramine. Thus, only a single achiral stereoisomer exists for [Co(tren)X2]+, where X is halide or pseudohalide. [2] In contrast, for [Co(trien)X2]+ five diastereomers are possible, four of which are chiral. In a few cases, tren serves as a tridentate ligand with one of the primary amine groups non-coordinated. Tren is a common impurity in the more common triethylenetetramine ("trien"). As a trifunctional amine, tren forms a triisocyanate when derivatized with COCl2.

It condenses with aldehydes to give imines. [3]

Structures of trigonal bipyramidal and octahedral complexes of the formulae M(tren)X (left, C3v symmetry) and M(tren)X2 (right, Cs symmetry). TrenCmpxs.png
Structures of trigonal bipyramidal and octahedral complexes of the formulae M(tren)X (left, C3v symmetry) and M(tren)X2 (right, Cs symmetry).

N-methylated derivatives

The permethylated derivative of tren has the formula N(CH2CH2NMe2)3. "Me6tren" forms a variety of complexes but, unlike tren, does not stabilize Co(III). Related amino-triphosphines are also well developed, such as N(CH2CH2PPh2)3 (m.p. 101-102 °C). This species is prepared from the nitrogen mustard N(CH2CH2Cl)3. [4]

N,N,N-trimethyltren, N(CH2CH2NHMe)3 is also available. [5]

Safety considerations

(H2NCH2CH2)3N, like other polyamines, is corrosive. [6] It causes severe skin burns and eye damage, is harmful if inhaled due to the destruction of respiratory tissues, is toxic if swallowed, and can be fatal in contact with skin. Its median lethal dose is 246 mg/kg, oral (rat), and 117 mg/kg, dermal (rabbit). It is also combustible. [7]

Related Research Articles

Ligand Ion or molecule that binds to a central metal atom to form a coordination complex

In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs often through Lewis Bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands".

Scorpionate ligand

The term scorpionate ligand refers to a tridentate ligand which would bind to a metal in a fac manner. The most popular class of scorpionates are the hydrotris(pyrazolyl)borates or Tp ligands. These were also the first to become popular. These ligands first appeared in journals in 1966 from the then little-known DuPont chemist of Ukrainian descent, Swiatoslaw Trofimenko. Trofimenko called this discovery "a new and fertile field of remarkable scope".

Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to around 40%. An estimated 270,000 tons were produced in 2005.

Salen ligand Chemical compound

Salen refers to a tetradentate C2-symmetric ligand synthesized from salicylaldehyde (sal) and ethylenediamine (en). It may also refer to a class of compounds, which are structurally related to the classical salen ligand, primarily bis-Schiff bases. Salen ligands are notable for coordinating a wide range of different metals, which they can often stabilise in various oxidation states. For this reason salen-type compounds are used as metal deactivators. Metal salen complexes also find use as catalysts.

Triethylenetetramine Chemical compound

Triethylenetetramine (TETA and trien), also called trientine (INN), is an organic compound with the formula [CH2NHCH2CH2NH2]2. This oily liquid is colorless but, like many amines, older samples assume a yellowish color due to impurities resulting from air-oxidation. It is soluble in polar solvents. The branched isomer tris(2-aminoethyl)amine and piperazine derivatives may also be present in commercial samples of TETA.

Trimethylphosphine Chemical compound

Trimethylphosphine is a neutral organophosphorus compound with the formula P(CH3)3, commonly abbreviated as PMe3. This colorless liquid has a strongly unpleasant odor, characteristic of alkylphosphines. The compound is a common ligand in coordination chemistry.

Organophosphines are organophosphorus compounds with the formula PRnH3−n, where R is an organic substituent. These compounds can be classified according to the value of n: primary phosphines (n = 1), secondary phosphines (n = 2), tertiary phosphines (n = 3). All adopt pyramidal structures. Organophosphines are generally colorless, lipophilic liquids or solids. The parent of the organophosphines is phosphine (PH3).

Lithium bis(trimethylsilyl)amide Chemical compound

Lithium bis(trimethylsilyl)amide is a lithiated organosilicon compound with the formula LiN(Si 3)2. It is commonly abbreviated as LiHMDS and is primarily used as a strong non-nucleophilic base and as a ligand. Like many lithium reagents, it has a tendency to aggregate and will form a cyclic trimer in the absence of coordinating species.

Tripodal ligand

Tripodal ligands are tri- and tetradentate ligands. They are popular in research in the areas of coordination chemistry and homogeneous catalysis. Because the ligands are polydentate, they do not readily dissociate from the metal centre. Many tripodal ligands have C3 symmetry.

Sodium tetraphenylborate Chemical compound

Sodium tetraphenylborate is the organic compound with the formula NaB(C6H5)4. It is a salt, wherein the anion consists of four phenyl rings bonded to boron. This white crystalline solid is used to prepare other tetraphenylborate salts, which are often highly soluble in organic solvents. The compound is used in inorganic and organometallic chemistry as a precipitating agent for potassium, ammonium, rubidium, and cesium ions, and some organic nitrogen compounds.

Denticity Number of atoms in a ligand that bond to the central atom of a coordination complex

In coordination chemistry, denticity refers to the number of donor groups in a given ligand that bind to the central metal atom in a coordination complex. In many cases, only one atom in the ligand binds to the metal, so the denticity equals one, and the ligand is said to be monodentate. Ligands with more than one bonded atom are called polydentate or multidentate. The denticity of a ligand is described with the Greek letter κ ('kappa'). For example, κ6-EDTA describes an EDTA ligand that coordinates through 6 non-contiguous atoms.

Compounds of zinc are chemical compounds containing the element zinc which is a member of the group 12 of the periodic table. The oxidation state of zinc in most compounds is the group oxidation state of +2. Zinc may be classified as a post-transition main group element with zinc(II). Zinc compounds are noteworthy for their nondescript behavior, they are generally colorless, do not readily engage in redox reactions, and generally adopt symmetrical structures.

Tris(2-pyridylmethyl)amine Chemical compound

Tris(2-pyridylmethyl)amine (abbreviated TPMA or TPA) is an organic compound with the formula (C5H4NCH2)3N. It is a tertiary amine with three picolyl substituents. It is a white solid that is soluble in polar organic solvents. It is a ligand in coordination chemistry.

Metal bis(trimethylsilyl)amides

Metal bis(trimethylsilyl)amides are coordination complexes composed of a cationic metal with anionic bis(trimethylsilyl)amide ligands and are part of a broader category of metal amides.

Metal amides

Metal amides (systematic name metal azanides) are a class of coordination compounds composed of a metal center with amide ligands of the form NR2. Amide ligands have two electron pairs available for bonding. In principle, they can be terminal or bridging. In these two examples, the dimethylamido ligands are both bridging and terminal:

Tris(trimethylsilyl)amine Chemical compound

Tris(trimethylsilyl)amine is the simplest tris(trialkylsilyl)amine which are having the general formula (R3Si)3N, in which all three hydrogen atoms of the ammonia are replaced by trimethylsilyl groups (-Si(CH3)3). Tris(trimethylsilyl)amine has been for years in the center of scientific interest as a stable intermediate in chemical nitrogen fixation (i. e. the conversion of atmospheric nitrogen N2 into organic substrates under normal conditions).

Tetradentate ligands are ligands that bind four donor atoms to a central atom to form a coordination complex. This number of donor atoms that bind is called denticity and is a way to classify ligands. Tetradentate ligands are common in nature in the form of chlorophyll which has a core ligand called chlorin, and heme with a core ligand called porphyrin. They add much of the colour seen in plants and humans. Phthalocyanine is an artificial macrocyclic tetradentate ligand that is used to make blue and green pigments.

2,2,2-Nitrilotriacetonitrile Chemical compound

Nitrilotriacetonitrile (NTAN) is a precursor for nitrilotriacetic acid, for tris(2-aminoethyl)amine and for the epoxy resin crosslinker aminoethylpiperazine.

Ethylenediaminediacetic acid (EDDA) is the organic compound with the formula C2H4(NHCH2CO2H)2. It is a derivative of two molecules of glycine, wherein the amines are linked. It is a white solid.

Transition metal imidazole complex

A transition metal imidazole complex is a coordination complex that has one or more imidazole ligands. Complexes of imidazole itself are of little practical importance. In contrast, imidazole derivatives, especially histidine, are pervasive ligands in biology where they bind metal cofactors.


  1. 1 2 "Tris(2-aminoethyl)amine". Sigma-Aldrich.
  2. Donald A. House "Ammonia & N-donor Ligands" in Encyclopedia of Inorganic Chemistry John Wiley & Sons, 2006. doi : 10.1002/0470862106.ia009.
  3. Schoustra, Sybren K.; Dijksman, Joshua A.; Zuilhof, Han; Smulders, Maarten M. J. (2021). "Molecular control over vitrimer-like mechanics – tuneable dynamic motifs based on the Hammett equation in polyimine materials". Chemical Science. 12 (1): 293–302. doi:10.1039/D0SC05458E. PMC   8178953 . PMID   34163597.
  4. R. Morassi, L. Sacconi "Tetradentate Tripod Ligands Containing Nitrogen, Sulfur, Phosphorus, and Arsenic as Donor Atoms" Inorganic Syntheses 1976, vol. 16 p. 174-180. doi : 10.1002/9780470132470.ch47
  5. Schmidt, H.; Lensink, C.; Xi, S. K.; Verkade, J. G. (1989). "New Prophosphatranes: Novel intermediates to five-coordinate phosphatranes". Zeitschrift für Anorganische und Allgemeine Chemie. 578: 75–80. doi:10.1002/zaac.19895780109.
  6. The Physical and Theoretical Chemistry Laboratory Oxford University MSDS
  7. "Safety Data Sheet". Sigma-Aldrich. July 1, 2014. Retrieved April 7, 2019.