Open aryl triazole receptors: planar sheets, spheres and anion binding

Abstract

The morphology of the aggregates formed from the self-assembly of aryl triazole amphiphiles is disrupted upon the binding of a bromide anion due to the conformational changes experienced by these receptors.

Increased Halide Recognition Strength by Enhanced Intercomponent Preorganisation in Triazolium Containing [2]Rotaxanes

“…Interestingly, downfield shifts in the axle phenyl proton b are also observed, suggesting the involvement of this proton in anion binding, as well as upfield movement of hydroquinone protons 4 and 5, consistent with increased donor-acceptor interactions upon chloride complexation. Similar peak movements were observed for rotaxane 17·PF 6 . Addition of the larger halide anions, bromide and iodide caused similar peak movements, but of a smaller magnitude, whereas only very small shifts were observed upon acetate addition.…”

“…Both new rotaxane host systems display impressive selectivity for the halide anions over larger, more basic acetate, with chloride and bromide being bound more than an order of magnitude more strongly than the oxoanion. Importantly, the rotaxanes containing aryl-substituted triazolium axles complex all anions significantly more strongly than the previously reported bis-alkyl-substituted rotaxane, with the bisaryl-substituted rotaxane 18·PF 6 showing slightly higher anion affinities than 17·PF 6 . Also of note is the observed preference for the smaller halide anions, chloride and bromide over larger iodide, which is significantly increased for the new aryl-substituted rotaxanes relative to the bis-alkyl-substituted host system.…”

“…The copper(I)-catalysed azide-alkyne cycloaddition (CuAAC) reaction [53,54] was used to synthesise the triazole containing axle components 13 and 14. Reaction of aryl azide 7 and alkyl-substituted alkyne 15, [55] in dichloromethane with catalytic [CuA C H T U N G T R E N N U N G (CH 3 CN) 4 ]A C H T U N G T R E N N U N G (PF 6 ), tris(benzyltriazolylmethyl)amine (TBTA) and diisopropylethyl amine (DIPEA) gave 13 in good yield (89 %). Reaction of 7 and 8 proceeded under similar conditions, but with the addition of TBA·F to remove the triisopropylsilyl group; it was found that far greater yields were obtained (85 %) when stoichiometric rather than catalytic copper(I) was used (< 20 % yield using 10 % catalyst loading), presumably due to competing decomposition of the unprotected alkyne in the slower catalytic reaction.…”

“…Chloride anion template removal by repeated washing with NH 4 PF 6(aq.) gave the hexafluorophosphate salts 17·PF 6 and 18·PF 6 for anion recognition studies. The new rotaxanes were characterised by 1 H, 13 C, 19 F, 31 P NMR spectroscopy and high resolution ESI mass spectrometry, as well as The interlocked nature of both rotaxanes was also confirmed by single crystal X-ray structural analysis.…”

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

“…As a new type of ionic liquids (ILs), triazoles have exhibited conspicuous advantages with nonvolatile, wide applicable temperatures and environmentally friendly properties [22,23]. In supramolecular chemistry, the specific 1,2,4-triazole ring as good building block has been frequently employed to construct various artificial cation, anion and molecular receptors [3,24], enzyme models and supramolecular catalysts [25,26] as well as nanometer materials [3,27], especially in supramolecular recognization, assembly [28,29] and in the development of supramolecular drugs [30][31][32]. All the above mentions have strongly shown an infinite space for the various applications of triazole compounds.…”