1,2,4-Triazole (as ligand in coordination compounds, Htrz abbreviation is sometimes used) is one of a pair of
isomericchemical compounds with
molecular formula C2H3N3, called
triazoles, which have a five-membered ring of two carbon atoms and three nitrogen atoms. 1,2,4-Triazole and its derivatives find use in a wide variety of applications.[1]
Structure and properties
1,2,4-Triazole is a planar molecule. The C-N and N-N distances fall into a narrow range 136 - 132 picometers, consistent with the aromaticity.[2] Although two tautomers can be envisioned, only one exists practically speaking.
1,2,4-Triazole is
amphoteric, being susceptible to both N-protonation and deprotonation in aqueous solution. The pKa of 1,2,4-triazolium (C2N3H4+) is 2.45. The pKa of the neutral molecule is 10.26.[3]
Synthesis and occurrence
Portion of the structure of {[Fe(triazolate)(triazole)2](BF4)}n.[4]
^Jeffrey, G. A.; Ruble, J. R.; Yates, J. H. (1983). "Neutron diffraction at 15 and 120 K and ab initio molecular-orbital studies of the molecular structure of 1,2,4-triazole". Acta Crystallographica Section B: Structural Science. 39 (3): 388–394.
Bibcode:
1983AcCrB..39..388J.
doi:
10.1107/S010876818300258X.
^Haasnoot, Jaap G. (2000). "Mononuclear, oligonuclear and polynuclear metal coordination compounds with 1,2,4-triazole derivatives as ligands". Coordination Chemistry Reviews. 200–202: 131–185.
doi:
10.1016/S0010-8545(00)00266-6.