Click synthesis and self-assembly of novel dendritic ethylene glycol/alkyl-substituted diarylated triazoles into supramolecular nanofibers

Abstract

Copper-catalyzed 1, 3-dipolar cycloaddition reaction between azides and alkynes under mild conditions has been known to exhibit high selectivity and good yields of 1, 2, 3-triazole. Additionally, 1, 2, 3-triazoles are used in various medical and pharmaceutical applications. Herein, we present novel low molecular weight organogelators from fluorescent ethylene glycol/alkyl-substituted 2, 6-diarylated pyridine 1, 2, 3-triazoles. Compact supramolecular architectures were created by the self-assembly of the synthesized gelators. The gel formation activity of the prepared ethylene glycol/alkyl-substituted 2, 6-diarylated pyridine triazoles were presented. The synthesis process was achieved by copper-catalyzed alkyne-azide cycloaddition (CuAAC) of ethylene glycol/alkyl-functionalized aromatic azide with aromatic alkyne bearing alkyl ester tails of various lengths. The ethylene glycol/alkyl-functionalized diaryl triazoles were investigated by 1H/13C NMR and FTIR spectroscopic methods. Triazoles with long ethylene glycol and/or alkyl ester tails showed an enhanced gelation activity as compared to those with shorter ethylene glycol and/or alkyl ester tails. The morphological features of the self-assembled ethylene glycol/alkyl-substituted arylated triazoles were studied by scanning electron microscopy (SEM), demonstrating supramolecular nanofibrous assemblies. Those supramolecular assemblies were forced by van der Waals and π-stacks interactions. Both antibacterial activity and cytotoxicity of the synthesized arylated triazole gelators were studied.