Tris(2-aminoethyl)amine is the

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

N(CH₂CH₂NH₂)₃. This colourless liquid is soluble in water and is highly basic, consisting of a

tertiary amine In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

center and three pendant

primary amine In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

groups. Tris(2-aminoethyl)amine is commonly abbreviated as tren or TREN. It is used a crosslinking agent in the synthesis of polyimine networks and a tripodal ligand in

coordination chemistry A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...

Supramolecular and polymer derivatives

Tris(2-aminoethyl)amine has been used to prepare molecular capsules and related supramolecular structures.

Metal complexes

Tren is a C3-symmetric,

tetradentate In chemistry, 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 method of classifying ligands. Tetradentate ligands are ...

chelating

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group 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 el ...

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 o(tren)X₂sup>+, where X is halide or pseudohalide. In contrast, for o(trien)X₂sup>+ five diastereomers are possible, four of which are chiral. In a few cases, tren serves as a

tridentate ligand A tridentate ligand (or terdentate ligand) is a ligand that has three atoms that can function as donor atoms in a coordination complex. Well-known tridentate ligands include diethylenetriamine with three nitrogen donor atoms, and the iminodiaceti ...

with one of the primary amine groups non-coordinated. Tren is a common impurity in the more common

triethylenetetramine Triethylenetetramine (TETA and trien), also known as trientine ( INN) when used medically, is an organic compound with the formula H2NHCH2CH2NH2sub>2. The pure free base is a colorless oily liquid, but, like many amines, older samples assume a y ...

("trien"). As a trifunctional amine, tren forms a tri

isocyanate In organic chemistry, isocyanate is the functional group with the formula . Organic compounds that contain an isocyanate group are referred to as isocyanates. An organic compound with two isocyanate groups is known as a diisocyanate. Diisocyan ...

when derivatized with COCl₂. TREN is known to react fast in the presence of (aromatic)

aldehydes In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...

to form an

imine In organic chemistry, an imine ( or ) is a functional group or organic compound containing a carbon–nitrogen double bond (). The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bon ...

. During this process, water is formed, making it a condensation reaction. Due to this fast and efficient reaction, TREN is commonly used in the preparation of polyimines.

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

Safety considerations

(H₂NCH₂CH₂)₃N, like other polyamines, is corrosive. 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 In toxicology, the median lethal dose, LD50 (abbreviation for " lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a given substance. The value of LD50 for a substance is the dose re ...

is 246 mg/kg, oral (rat), and 117 mg/kg, dermal (rabbit). It is also combustible.

References

{{reflist Aminoethyl compounds Tertiary amines Tripodal ligands