Synthesis, Structure, and Photochemical Behavior of [5]Heli-viologen Isomers

The
syntheses of isomeric helical viologens that have potential
applications in supramolecular chemistry and catalysis have been developed.
The structures of the molecules and their solid-state packing motifs
have been determined by X-ray crystallography. Computational studies
demonstrate that the magnitude of their racemization barriers is primarily
determined by the identity of the helical scaffold and is insensitive
to the placement of the viologen functional group. The isomers are
similar in their photophysical behavior but very different in their
photochemical behavior.