Controlling the sign of Excimer‐Origin Circularly Polarised Luminescence by Balancing Hydrophilicity/Hydrophobicity in Bipyrenyl Arginine Peptides.

Determining the conformation of a chiral luminescent molecule in its ground state as well as in its photoexcited state is difficult. In the case of a pyrenyl peptide, the sign of its circularly polarised luminescence (CPL) is determined by the solvent or the intramolecular distance between its pyrenyl units; consequently, a new method for controlling CPL in water is required. Herein, we report that chiral LL‐oligopeptide luminophores bearing two fluorescent pyrenyl and hydrophilic arginine units exhibit clear excimer‐origin circularly polarised luminescence (CPL) at 480–510 nm in aqueous solution. The CPL sign is tuneable by altering the number and positions of the arginine units on the edges of the chiral peptide backbone. [ABSTRACT FROM AUTHOR]