Helical Inversion of Peptide‐based Supramolecular Co2+ Complexes

• Published in: Bulletin of the Korean Chemical Society Vol. 39; no. 8; pp. 988 - 994
• Main Authors: Kim, Ka Young, Kim, Jaehyeong, Park, Hyesong, Choi, Yeonweon, Kwon, Ki‐Young, Jung, Jong Hwa
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley‐VCH Verlag GmbH & Co. KGaA 01.08.2018; 대한화학회
• Subjects: Cobalt complex; Helicity; Supramolecular polymer; 화학
• ISSN: 1229-5949; 0253-2964; 1229-5949
• DOI: 10.1002/bkcs.11540

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‐1 in 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.