2.1. Materials

4,4’-(Perfluoropropane-2,2-diyl)diphenol, 4,4’-sulfonyldiphenol, 4,4’-oxydiphenol, 4-nitrophthalonitrile and 4-nitrobenzene-1,2-diamine were obtained from AK Scientific Inc Company (San Francisco, USA). 4-Nitrobenzoyl chloride, Eaton’s reagent, anhydrous N,N-dimethylformamide (DMF), anhydrous N,N-dimethylacetamide (DMAc), anhydrous pyridine (Py), acetic anhydride (Ac₂O) and 1-butyl-3-methylimidazolium bromide ([Bmim]Br) were obtained from Sigma-Aldrich-Merck Company (Milwaukee, WI, USA). 2-(4-Aminophenyl)-1H-benzimidazole-5-amine (p-DABI) was synthesized according to the literature [32]. All other reagents and solvents were purchased commercially as analytical-grade and used without further purification.