Long Range Electronic Effects on the Host-Guest Complexation within the Oxygen Depleted 5,5'-Bicalixarene Cavities

J Org Chem. 2023 Nov 17;88(22):15983-15988. doi: 10.1021/acs.joc.3c01566. Epub 2023 Oct 31.

Abstract

We report the synthesis of a series of the oxygen-depleted conjugated 5,5'-Bicalix[4]arene compounds bearing various substituents at the terminal positions of the conjugated chain and their fluorescence response to the presence of a cationic N-methylpyridinium guest. The complexation of this cation within the bicalixarene cavity results in the fluorescence quenching, with the host molecules bearing electron-donating groups demonstrating a stronger fluorescence response. These results show the importance of the electronic effects on the host-guest complexation within the hydrophobic calixarene scaffolds.