Tris(2-aminoethyl)amine

Tris(2-aminoethyl)amine

Identifiers
CAS Number	4097-89-6
Beilstein Reference	1739626
ChEBI	CHEBI:30631
ChEMBL	ChEMBL19823
ChemSpider	70131
EC Number	223-857-4
Gmelin Reference	27074
Jmol interactive 3D	Image
MeSH	tris(2-aminoethyl)amine
PubChem	[https://pubchem.ncbi.nlm.nih.gov/compound/77731 pubchem from PubChem 77731 pubchem from PubChem]
RTECS number	KH8587082
UN number	2922
InChI InChI=1S/C6H18N4/c7-1-4-10(5-2-8)6-3-9/h1-9H2 Key: MBYLVOKEDDQJDY-UHFFFAOYSA-N
SMILES NCCN(CCN)CCN
Properties
Chemical formula	C6H18N4
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)
Solubility in water	Miscible
log P	−2.664
Vapor pressure	3 Pa (at 20 °C)
Refractive index (nD)	1.497
Thermochemistry
Std enthalpy of formation (ΔfH^o298)	−74.3–−72.9 kJ mol^−1
Std enthalpy of combustion (ΔcH^o298)	−4860.6–−4859.2 kJ mol^−1
Hazards
Safety data sheet	fishersci.com
GHS pictograms
GHS signal word	DANGER
GHS hazard statements	H301, H310, H314
GHS precautionary statements	P280, P302+350, P305+351+338, P310
EU classification (DSD)	T
R-phrases	R22, R24, R34
S-phrases	S26, S36/37/39
Flash point	113 °C (235 °F; 386 K)
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	117 mg kg^−1 (dermal, rabbit) 246 mg kg^−1 (oral, rat)
Related compounds
Related amines	Dimethylamine Trimethylamine N-Nitrosodimethylamine Diethylamine Triethylamine Diisopropylamine Dimethylaminopropylamine Diethylenetriamine N,N-Diisopropylethylamine Triisopropylamine Mechlorethamine HN1 (nitrogen mustard) HN3 (nitrogen mustard)
Related compounds	Unsymmetrical dimethylhydrazine Biguanide Dithiobiuret Agmatine
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, C_3v symmetry) and M(tren)X₂ (right, C_s symmetry).

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] 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

• Sigma Aldrich