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Sequence and Structure of Peptoid Oligomers Can Tune the Photoluminescence of an Embedded Ruthenium Dye
Author(s) -
Zborovsky Lieby,
TiggerZaborov Hagar,
Maayan Galia
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201901494
Subject(s) - peptoid , ruthenium , chromophore , circular dichroism , quenching (fluorescence) , chemistry , sequence (biology) , fluorescence , luminescence , bipyridine , crystallography , photochemistry , combinatorial chemistry , peptide , materials science , crystal structure , organic chemistry , biochemistry , physics , optoelectronics , quantum mechanics , catalysis
The understanding of structure–function relationships within synthetic biomimetic systems is a fundamental challenge in chemistry. Herein we report the direct correlation between the structure of short peptoid ligands—N‐substituted glycine oligomers incorporating 2,2′‐bipyridine groups—varied in their monomer sequence, and the photoluminescence of Ru II centers coordinated by these ligands. Based on circular dichroism and fluorescence spectroscopy we demonstrate that while helical peptoids do not affect the fluorescence of the embedded Ru II chromophore, unstructured peptoids lead to its significant decay. Transmittance electron microscopy (TEM) revealed significant differences in the arrangements of metal‐bound helical versus unstructured peptoids, suggesting that only the latter can have through‐space interactions with the ruthenium dye leading to its quenching. High‐resolution TEM enabled the remarkable direct imaging of singular ruthenium‐bound peptoids and bundles, supporting our explanation for structure‐depended quenching. Moreover, this correlation allowed us to fine‐tune the luminescence properties of the complexes simply by modifying the sequence of their peptoid ligands. Finally, we also describe the chiral properties of these Ru–peptoids and demonstrate that remote chiral induction from the peptoids backbone to the ruthenium center is only possible when the peptoids are both chiral and helical.