Toward the rational design of molecular rotors ion sensors based on α,γ-cyclic peptide dimers

A dimer-forming self-assembling cyclic hexapeptide with a control register and a large association constant in water is described. The self-assembly process is followed by pyrene-excimer emission and the main diastereomeric dimer present in solution is switched by controlled addition of divalent cations (e.g., Ca, Mg) or oxalic acid.