Aromatic plane effect study in pseudorotaxane construction between 'Texas-sized' molecular box and carboxylate anions

This study focused on the aromatic plane effect of the binding modes between 'Texas-sized' molecular box and carboxylate anion species. The molecular box, namely cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)-[2](1,4-dimethylenebenzene) (14+; studied as the PF6− salt), easily constructs interpenetrated structures (i.e., pseudorotaxanes) with carboxylate anions via the introduction of aromatic rings. As revealed by 1H NMR titration, two-dimensional nuclear Overhauser effect spectroscopy (NOESY), UV-Vis spectroscopic study, and electrospray ionization mass spectrometry (ESI-MS), the determination effect of aromatic plane in the binding modes between 14+ and carboxylate anions was studied in detail. This research reveals the important role of aromatic plane substitute groups on anions for building anion-induced interpenetrated self-assembly structures.