C-I•••π Halogen Bonding Driven Supramolecular Helix of Bilateral N-Amidothioureas Bearing β-Turns

We report the first example of C-I center dot center dot center dot pi halogen bonding driven supramolecular helix in highly dilute solution of micromolar concentration, using alanine based bilateral I-substituted N-amidothioureas that contain helical fragments, the beta-turn structures. The halogen bonding interactions afford head-to-tail linkages that help to propagate the helicity of the helical fragments. In support of this action of the halogen bonding, chiral amplification was observed in the supra molecular helix formed in acetonitrile solution. The present finding provides alternative tools in the design of self-assembling macromolecules.