Materials. All solvents and reagents were used as supplied. Measurements. The 1 H NMR spectra were recorded at 400 MHz and 500 MHz and 13 C NMR spectra were recorded at 125 MHz with a JEOL-EX400 and ECA500 spectrometers. N-(8-Bromooctyl)-trimetylammonium hexafluorophosphate and per-methylated pillar[5]arene (2) were synthesized according to the previous papers. 1,2 3. To a solution of 2 (2.00 g, 2.68 mmol) in anhydrous dichloromethane (80 mL), boron tribromide (0.228 mL, 2.41 mmol) was added.

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... e mixture was stirred at 25 o C for 45 minutes under nitrogen. Then, water was added into the mixture. The organic layer was dried over anhydrous Na 2 SO 4 . After filtration, the filtrate was poured into methanol and the resulting precipitate was collected by filtration. Column chromatography (silica gel; chloroform : acetone = 18 : 1) afforded a white solid (3, 0.44 g, 0.60 mmol, Yield: 22%).