Ruthenium-Vinylhelicenes: Remote Metal-Based Enhancement and Redox Switching of the Chiroptical Properties of a Helicene Core

Introducing metal-vinyl ruthenium moieties onto [6]­helicene
results
in a significant enhancement of the chiroptical properties due to
strong metal–ligand electronic interactions. The electro-active
Ru centers allow the achievement of the first purely helicene-based
redox-triggered chiroptical switches. A combination of electrochemical,
spectroscopic, and theoretical techniques reveals that the helicene
moiety is a noninnocent ligand bearing a significant spin density.