Not to be confused with triazine or triazane.
Structural formula of triazene
Space-filling model of the triazene molecule
IUPAC name
Systematic IUPAC name
15056-34-5 YesY
3D model (Jmol) Interactive image
ChEBI CHEBI:35468 YesY
ChemSpider 102956 YesY
PubChem 115034
Molar mass 45.05 g·mol−1
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g., nitroglycerin Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Other anions
Related Binary azanes
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Triazene, also known as triazanylene, is an unsaturated inorganic compound having the chemical formula N3H3. It has one double bond, and is the second-simplest member of the azene class of hydronitrogen compounds, and is not found in nature. It is also the name given to the functional group consisting of an amine directly bonding to an azo group, i.e. with the linkage R1R2N-N=NR3 where R1, R2 and R3 are substituents. The functional group is also called a diazoamino group (but only one of the two substituents R1 and R3 may be hydrogen) because it is related to a diazo group.


At room temperature, triazene is a gas and, as with many other azenes, it is also coloured with a strong and unpleasant smell. Triazene has a higher density and boiling point than diazene due to its greater mass. It has a slightly lower boiling point than triazane and is thus more volatile. It has strong polar bonds, and the molecule has a large dipole moment due to its reduced symmetry.

Triazene has the same empirical formula as cyclotriazane but their atoms are connected in different ways, making these molecules structural isomers.

Medical uses

Some anti-cancer medications are called triazenes because they contain a triazene functional group. The triazenes are a group of alkylating agents used to treat cancer. Examples include dacarbazine and temozolamide. They work by methylating guanine at the O-6 and N-7 position.


To date, the only proven method to produce triazene is the spontaneous decomposition of tetrazane into triazene and ammonia.


General structure of a triazene

A well-known example of triazene is a diphenyl derivative,[2] PhNH-N=NPh (m.p. 100 °C, CAS #136-35-6). It is prepared from phenyldiazonium salts and aniline in the presence of base:

PhN2+ + PhNH2 → PhNHN=NPh + H+


Triazenes have been used as in situ diazonium source. Triazenes decompose in the presence of protonating or alkylating agents into quaternary amines and diazonium salts. A strategy for the protection and deprotection of sensitive secondary amines is based on this principle.[3]

Triazenes can be reacted with sodium sulfide in the presence of trichloroacetic acid to give the corresponding thiophenols.[4]

Triazene cleavage

In another example, the synthesis of cinnoline was accomplished by Richter reaction of triazene-masked diazonium ion.[5]

See also


  1. "triazene (CHEBI:35468)". Chemical Entities of Biological Interest. EMBL-EBI.
  2. Hartman, W. W.; Dickey, J. B. (1934). "Diazoaminobenzene". Org. Synth. 14: 24.; Coll. Vol., 2, p. 163
  3. Lazny, R.; Poplawski, J.; Köbberling, J.; Enders, D.; Bräse, S. (1999). "Triazenes: A Useful Protecting Strategy for Sensitive Secondary Amines". Synlett. 1999 (8): 1304–6. doi:10.1055/s-1999-2803.
  4. Kazem-Rostami, M.; Khazaei, A.; Moosavi-Zare, A. R.; Bayat, M.; Saednia, S. (2012). "Novel One-Pot Synthesis of Thiophenols from Related Triazenes under Mild Conditions". Synlett. 23 (13): 1893–6. doi:10.1055/s-0032-1316557.
  5. Goeminne, A.; Scammells, P. J.; Devine, S. M.; Flynn, B. L. (2010). "Richter cyclization and co-cyclization reactions of triazene-masked diazonium ions". Tetrahedron Letters. 51 (52): 6882–5. doi:10.1016/j.tetlet.2010.10.122.
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