Helicity control of an indolocarbazole foldamer by chiral organic anions.

Chiral organic anions such as camphorsulfonates and cAMP give rise to the preferential formation of a one-handed helix of an indolocarbazole foldamer, thus inducing characteristic circular dichroic (CD) signals. Moreover, the on and off switching of the chiroptical signal can be operated by acid and base chemistry which efficiently controls the association and dissipation of the foldamer and cAMP.