Tris(2-aminoethyl)amine

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Tris(2-aminoethyl)amine

IUPAC name	Tris(2-aminoethyl)amine
Other names	2,2',2-Nitrilotriethylamine 2,2',2-Triaminotriethylamine TAEA 4-(2-aminoethyl)diethylenetriamine nitrilotris(ethylamine) tris(aminoethyl)amine tris(beta-aminoethyl)amine Tren
Identifiers
CAS number	[4097-89-6]
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
Main hazards	Corrosive
R-phrases	22-24-34
S-phrases	26-36/37/39-45
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Tris(2-aminoethyl)amine is the chemical 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.

1 Coordination chemistry
- 1.1 Related tripodal ligands
2 Organic chemistry
3 Safety considerations
4 References

[edit] 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.

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

Structures of trigonal bipyramidal and octahedral complexes of the formulae M(tren)X (left, C_3v symmetry) and M(tren)X₂ (right, C_s symmetry).

[edit] 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 itself, does not stabilize Co(III). Related 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.

[edit] 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]

[edit] Safety considerations

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

[edit] References

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