Synthesis of a deep cavity calix[4]arene by fourfold Sonogashira cross-coupling reaction and selective fluorescent recognition toward p-nitrophenol

A new tetranaphthyl-calix[4]arene (C4N4) was synthesized by a fourfold Sonogashira cross-coupling reaction, and exhibited high affinity and selectivity for p-nitrophenol (3c) by fluorescence spectroscopy. The NMR, AFM, IR, MALDI-TOF mass spectroscopy, and computational calculations revealed the formation of a host–guest complex driven by π–π stacking interactions.