The cucurbituril ‘portal’ effect

Abstract

This work focuses on the effect of cucurbit[n]uril (CBn) hosts on the microenvironment of molecular subunits that are located adjacent to the CBn binding site in inclusion complexes. The set of data presented here includes previously reported electrochemical and electron paramagnetic resonance spectroscopic data, primarily obtained with ferrocene-containing guests, as well as new electrochemical data recorded with 4,4′-bipyridinium (viologen) derivatives. Most of the data were obtained with cucurbit[7]uril (CB7) complexes, and the rest were collected with cucurbit[8]uril (CB8) complexes. The experimental data compiled here clearly suggest that the microenvironment adjacent to the CBn portals in the complexes exhibits increased polarity compared with the bulk aqueous solution.