Tris(2-aminoethyl)amine

Tris(2-aminoethyl)amine
Identifiers
CAS number 4097-89-6 Y
PubChem 77731
RTECS number KH8587082
Properties
Molecular formula (NH2CH2CH2)3N
Molar mass 146.236 g/mol
Appearance colourless
Density 0.977  g/cm3
Melting point

−16 °C

Boiling point

265 °C

Solubility in water miscible
Solubility polar organic solvents
Hazards
MSDS Fisher Scientifc MSDS
R-phrases 22-24-34
S-phrases 26-36/37/39-45
Main hazards Corrosive
 Y (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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.

Contents

Coordination chemistry

Tren is a tripodal, 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 diastereoiomers 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.

Related tripodal ligands

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]

The tripodal ligand of greatest commercial significance is nitrilotriacetate, N(CH2CO2-)3.

Organic chemistry

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

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

References

  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