Helical Inversion of Peptide‐based Supramolecular Co2+Complexes
Ka Young Kim, Jaehyeong Kim, Hyesong Park, Yeonweon Choi, Ki‐Young Kwon, Jong Hwa Jung
Bulletin of the Korean Chemical Society
Herein, we report the helical inversion of supramolecular polymeric complexes of Co2+containing a peptide‐based ligand comprising one alanine and three glycine moieties and an achiral terpyridine group. The helicity of the peptide‐based supramolecular polymer is controlled via strain‐induced chirality at different stoichiometric ligand/Co2+ ratios. The supramolecular polymer S‐1 adopts octahedral geometry with right‐handed helicity (P‐type) in the presence of <0.7 equiv of Co2+. In contrast, it adopts coexisting octahedral and square‐pyramidal geometries in the presence of 1.0 equiv of Co2+ and presents left‐handed helicity (M‐type). The helicities of the supramolecular polymer R‐1 with Co2+, prepared using the chirally opposite ligand, were completely opposite to those of S‐1. Furthermore, the circular dichroism intensities of supramolecular polymers S‐1 and R‐1in the presence of Co2+ were 900–1500 times higher than those of free S‐1 and R‐1. In addition, the helical inversion was completely reversible and controllable by the addition of more Co2+ or ligand.
Circular dichroism, Stereochemistry, Chemical stability, Coordination chemistry, Polymers, Inorganic chemistry