Anion-Responsive Pseudo[3]rotaxane from a Difunctionalized Pillar[4]arene[1]quinone and a Bis-Imidazolium Cation

Org Lett. 2020 Oct 16;22(20):7831-7836. doi: 10.1021/acs.orglett.0c02710. Epub 2020 Oct 2.

Abstract

Synthesis of a new functionalized pillar[4]arene[1]quinone and its host-guest complexation with a bis-imidazolium dication was demonstrated. 1D/2D NMR spectroscopic analyses and high-resolution mass spectrometric analyses showed the formation of the pseudo[3]rotaxane assembly upon host-guest complexation. 1H NMR titration experiments revealed the role of hydrogen bonding motifs in bringing positive cooperativity by comparing the binding constants for the host-guest complexation of pillar[4]arene[1]quinone with a bis-imidazolium guest. Anion-responsiveness of the pseudo[3]rotaxane assembly was also demonstrated.