Triazole: a unique building block for the construction of functional materials

Abstract

Over the past 50 years, numerous roads towards carbon-based materials have been explored, all of them being paved using mainly one functional group as the brick: acetylene. The acetylene group, or the carbon-carbon triple bond, is one of the oldest and simplest functional groups in chemistry, and although not present in any of the naturally occurring carbon allotropes, it is an essential tool to access their synthetic carbon-rich family. In general, two strategies towards the synthesis of π-conjugated carbon-rich structures can be employed: (a) either the acetylene group serves as a building block to access acetylene-derived structures or (b) it serves as a synthetic tool to provide other, usually benzenoid, structures. The recently discovered copper-catalysed azide-alkyne cycloaddition (CuAAC) reaction, however, represents a new powerful alternative: it transforms the acetylene group into a five-membered heteroaromatic 1H-1,2,3-triazole (triazole) ring and this gives rise to new opportunities. Compared with all-carbon aromatic non-functional rings, the triazole ring possesses three nitrogen atoms and, thus, can serve as a ligand to coordinate metals, or as a hydrogen bond acceptor and donor. This Feature Article summarises examples of using the triazole ring to construct conjugation- and/or function-related heteroaromatic materials, such as tuneable multichromophoric covalent ensembles, macrocyclic receptors or responsive foldamers. These recent examples, which open a new sub-field within organic materials, started to appear only few years ago and represent "a few more bricks" on the road to carbon-rich functional materials.

Synthesis and NMR Analysis of 1,4‐Disubstituted 1,2,3‐Triazoles Tethered to Pyridine, Pyrimidine, and Pyrazine Rings

“…[1] This changed dramatically with the discovery of the copper-catalysed azide-alkyne cycloaddition to produce the triazole ring in a reaction that meets all the criteria of "click" chemistry (CuAAC, Scheme 1). [2,3] Since then, the so called "click" triazole has found widespread application in almost every research area of chemical, biochemical, and materials sciences.…”

“…As the target heteroaryl triazoles were designed to serve as advanced ligands or ligand precursors for metal coordination, they were fully characterized by 1 H, 13 C, and 15 N NMR spectroscopy. The resonances were assigned on the basis of 1D and 2D NMR experiments.…”

“…The resonances were assigned on the basis of 1D and 2D NMR experiments. 1 H-15 N gs-HMBC was used as a practical tool to determine 15 N NMR chemical shifts at the natural abundance level of the 15 N isotope.…”

Computational investigations of click-derived 1,2,3-triazoles as keystone ligands for complexation with transition metals: a review

“…8,79,80 These bidentate click ligands form rhenium(I) complexes with a 1 : 1 metal : ligand ratio. The complexes of these ligands have wide applications in electronic 81,82 and luminescent 29,[83][84][85][86][87][88][89] materials, catalysts, [90][91][92] and in metallo-pharmaceuticals.…”

Current Developments in the Syntheses of 1,2,4-Triazole Compounds

“…2) have been extensively employed for agricultural produc tion. In material sciences, triazoles as new types of functional materials have displayed enormous potentiality in luminescent, magnetic and electron transport materials [3,[14][15][16][17][18][19]. In chemical aspects, as corrosion inhibitors, triazole-derived compounds may easily form -coordination bonds with various metal ions to inhibit the corrosion of metals [20,21]; as light stabilizers, triazole derivatives with low volatility and high thermostability have been widespreadly applied in paints, food packages as well as sunscreen agents [11].…”