Viologen cyclophanes: redox controlled host-guest interactions

Chem Commun (Camb). 2015 Nov 11;51(87):15772-5. doi: 10.1039/c5cc06041a.

Abstract

Viologens can exist in three redox states varying from dicationic to neutral. This work emphasizes the control of the host-guest properties in bis-viologen cyclophanes. Two flexible cyclophanes were prepared by a cyclisation method sensitive to the odd/even number of carbons in the flexible chains linking two viologens. C5 and C7 cyclophanes were characterised by X-ray diffraction in their tetracationic state and their diradical dicationic state. In the presence of tetrathiafulvalene or methyl viologen as guests, inclusion complexes were obtained, including a mixed valence species.