[n]Cycloparaphenylene-Pillar[5]arene Bismacrocycles: Their Circularly Polarized Luminescence and Multiple Guest Recognition Properties

Both pillarn]arenes (Pn]As) and n]cycloparaphenylenes (n]CPPs) play an important role in supramolecular chemistry. Herein, we report the precise synthesis of two multifunctional bismacrocycles n]CPP-P5]A by integrating P5]A into the n]CPP backbone. The photoluminescence quantum yield (Φ_F) of the bismacrocycles was found to show a dramatic increase relative to the corresponding n]CPPs. The chiral enantiomers (pR)/(pS)-8]CPP-P5]A were successfully isolated by chiral HPLC, and showed promising properties of circularly polarized luminescence (g_lum≈0.02). In addition, n]CPP-P5]A bismacrocycles are capable of binding pyridinium salts and fullerene derivatives with high affinity and specificity within the two distinct cavities. Transient absorption studies showed that photo-induced electron transfer occurs in 10]CPP-P5]A?C₆₀ complex. Our results suggest that n]CPP-P5]A are potentially useful in CPL-active materials, multiple guest recognition and supramolecular polymer preparation.