NHC Polymeric Particles Obtained by Self-Assembly and Click Approach of Calix[4]Arene Amphiphiles as Support for Catalytically Active Pd Nanoclusters

Abstract

A new polymeric NHC carrier was synthesized by sequential supramolecular self-assembly and copper-catalyzed azide-alkyne cycloaddition (CuAAC) of amphiphilic imidazolium calix[4]arenes with octyl lipophilic fragments. Obtained polytriazole-imidazolium particles were found as monodisperse submicron particles, with the average diameter of 236 ± 34 nm and average molecular weight of 1380 ± 96 kDa. Successful CuAAC polymerization has been proved using IR spectroscopy and high-resolution ESI mass spectrometry. Polymeric particles, as well as aggregates made from precursor macrocycles, were decorated by Pd clusters (2 nm) for further catalytic investigations. Pd nanoclusters, supported on the polymeric surface, were found highly catalytically active in the model reduction of p-nitrophenol, giving reaction rates an order of magnitude higher compared to literature examples. The reaction was recycled using the same catalyst five times without any loss of activity.

New Carboxytriazolyl Amphiphilic Derivatives of Calix[4]arenes: Aggregation and Use in CuAAC Catalysis

“…After click reactions, the 13 S4d). It was shown earlier for imidazolium derivatives of calix [4]arene that when using a mild ionization method such as electrospray, signals from various quinomethide structures can also be observed in high-resolution mass spectra in addition to the peaks of molecular doubly charged ions [32].…”

Copper(I)-Catalyzed Alkyne–Azide Cycloaddition (CuAAC) “Click” Reaction: A Powerful Tool for Functionalizing Polyhydroxylated Platforms

“…p -H-calix­[4]­arene 80 , presynthesized from p - -butyl-calix[4]­arene using de- tert -butylation with AlCl 3 in the presence of phenol, was treated by butyl bromide to give bis-O-butyl derivative 81 , which was then incorporated into a Blanc chloromethylation to give calix[4]­arene 82 with a nearly qualitative yield (Scheme B). The final step was the reaction of calix[4]­arene 83 with 1-(3-azidopropyl)-1 H -imidazole or 1-(hex-5-yn-1-yl)-1 H -imidazole. , …”

“…The final step was the reaction of calix [4]arene 83 with 1-(3-azidopropyl)-1H-imidazole or 1-(hex-5-yn-1-yl)-1H-imidazole. 83,84 Finally, Table 2 85−93 shows examples of the incorporation of other organic molecules, such as cationic, ionic, nonionic, allyl, benzyl, triphenylene, thiazole acetate, dimethyl acetylenedicarboxylate, and polyammonium, along with their required conditions. This comparative table allows us to show the great versatility that the copper-catalyzed cycloaddition reaction can have between an alkyne group and an azide group (CuAAC) in the generation of new calixarene/resorcinarene derivatives.…”

“…The final step was the reaction of calix[4]arene 83 with 1-(3-azidopropyl)-1 H -imidazole or 1-(hex-5-yn-1-yl)-1 H -imidazole. 83 , 84 …”

Tools to enable the study and translation of supramolecular amphiphiles

“…49 Examples of HRMS methodologies include, time of flight (ToF) MS, orbitrap MS and Fourier-transform ion cyclotron resonance (FT-ICR) MS. 50 There are multiple examples for the use of MS (sometimes used in combination with ion mobility spectrometry) for characterisation of supramolecular assemblies and amphiphiles throughout literature. [51][52][53][54] The most common use of this technique within the field of chemistry is the determination of the m/z for a single molecule. However, there has always been a desire to develop HRMS methodologies to characterise noncovalent interactions and subsequent molecular morphologies.…”