Chemistry of 1,2,3-Triazolium Salts

Abstract

1,2,3-Triazolium salts have been known for a long time. However, their potential as ionic liquids and catalysts was recognized only quite recently. 1,2,3-Triazolium ionic liquids can serve as solvent, as catalyst, as hosts in anion recognition and as components of molecular machines. The major trends in application involve tethering catalytically active species such as (S)-proline with triazolium ionic liquids and the use as anion recognizing organocatalysts. Such catalysts are interesting not only due to their recyclability but also because of their outstanding tuneable properties. They can have wide liquid range, thermal stability, tuneable polarity, low flammability, tuneable solubility and low vapour pressure along with ease of separation. The syntheses of 1,2,3-triazolium salts are mainly based on the copper catalysed azide-alkyne cycloaddition (CuAAC) as the most famous click reaction, and subsequent N-alkylation of the resulting 1,2,3-triazoles. This synthetic route has the advantage of having four structural units, i.e. the alkyne, the azide, the alkylating agent and the counter anion that can be manipulated in order to tune the properties of the resulting ionic liquid. Unlike the imidazolium ionic liquids 1,2,3-triazolium salts do not have an acidic proton at position 2, which could make them inappropriate for reactions under basic conditions. The low acidity of 1,2,3triazolium salts in position 4 is exploited in the formation of 1,2,3-triazol-4-ylidene metal complexes with marked catalytic properties.

Poly(1,2,3-triazolium)s: a new class of functional polymer electrolytes

“…41,42 The synthesis of TILs generally involves the initial preparation of 1,4-dialkyl-1,2,3triazoles, followed by the N-alkylation of the N-3 position and optional anion exchange reaction (Fig. 5).…”

Synthesis and antioxidant action of chitosan derivatives with amino-containing groups via azide-alkyne click reaction and N-methylation

“…Over the last decade, Cuprous-catalyzed azide-alkyne cycloaddition (CuAAC) has emerged as a useful and attractive tool in functionalization of chitosan because of its modularity, chemoselectivity, efficiency, and versatility and a growing effort has been devoted to the employment of CuAAC reaction for the functionalization of chitosan derivatives (Meng & Edgar, 2016;Tiwari et al, 2016). Moreover, it is recently that 1,3,4-trisubstituted-1,2,3-triazolium-based cations have been developed by N-alkylation of 1,2,3-triazoles by alkyl halides or alkyl triflates with the outstanding tunable structural diversity to optimize the properties (Yacob & Liebscher, 2015). Their potential as stereoselective organocatalysts (Ohmatsu, Hamajima, & Ooi, 2012), ionic liquids (Mudraboyina et al, 2014), and conducting materials (Jourdain, Serghei, & Drockenmuller, 2016) have been recognized and established.…”

Energetic Materials Based on N-substituted 4(5)-nitro-1,2,3-triazoles

“…Along with that, inaccessible N3-substitution products in the series of isomeric N-substituted 4-nitro-1,2,3-triazoles are of special interest for the development of high-energy [26,27], ionic [28][29][30], and polymeric materials [31] and metal complexes [32,33]. Due to the low accessibility, N3-substitution products are almost understudied.…”