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Skeletal formula of tris(2-aminoethyl)amino
3D model (JSmol)
ECHA InfoCard 100.021.689
EC Number 223-857-4
MeSH [{{{MeSH}}} {{{MeSH}}}]
RTECS number KH8587082
UN number 2922
Molar mass 146.24 g·mol−1
Appearance Colourless liquid
Odor Ichtyal, ammoniacal
Density 977 mg mL−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)
−74.3–−72.9 kJ mol−1
−4860.6–−4859.2 kJ mol−1
Safety data sheet
GHS pictograms The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
H301, H310, H314
P280, P302+350, P305+351+338, 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)
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).
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Infobox references

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, it is the archetypal tripodal ligand of interest 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.[1] 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.

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

Related tripodal ligands[edit]

The permethylated derivative of tren is also well known. With 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.[2] Tren is a common impurity in the more common triethylenetetramine ("trien"). As a trifunctional amine, tren forms a triisocyanate when derivatized with COCl2.[3]

Safety considerations[edit]

(NH2CH2CH2)3N, like other polyamines, is corrosive.[4]


  1. ^ Donald A. House "Ammonia & N-donor Ligands" in Encyclopedia of Inorganic Chemistry John Wiley & Sons, 2006. doi:10.1002/0470862106.ia009.
  2. ^ 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
  3. ^ Pressure Chemical
  4. ^ The Physical and Theoretical Chemistry Laboratory Oxford University MSDS