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Detection and Chiral Recognition of α‐Hydroxyl Acid through 1 H and CEST NMR Spectroscopy Using a Ytterbium Macrocyclic Complex
Author(s) -
He Haonan,
Zhao Kelu,
Xiao Long,
Zhang Yi,
Cheng Yi,
Wan Sikang,
Chen Shizhen,
Zhang Lei,
Zhou Xin,
Liu Kai,
Zhang Hongjie
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201912072
Subject(s) - chemistry , cyclen , chirality (physics) , nuclear magnetic resonance spectroscopy , side chain , ytterbium , proton nmr , chemical shift , spectroscopy , stereochemistry , organic chemistry , materials science , chiral anomaly , physics , optoelectronics , fermion , doping , quantum mechanics , nambu–jona lasinio model , polymer
Chiral α‐hydroxyl acids are of great importance in chemical synthesis. Current methods for recognizing their chirality by 1 H NMR are limited by their small chemical shift differences and intrinsic solubility problem in organic solvents. Herein, we developed three YbDO3A(ala) 3 derivatives to recognize four different commercially available chiral α‐hydroxyl acids in aqueous solution through 1 H NMR and chemical exchange saturation transfer (CEST) spectroscopy. The shift difference between chiral α‐hydroxyl acid observed by proton and CEST NMR ranged from 15–40 and 20–40 ppm, respectively. Our work demonstrates for first time, that even one chiral center on the side‐arm chain of cyclen could set the stage for rotation of the other two non‐chiral side chains into a preferred position. This is ascribed to the lower energy state of the structure. The results show that chiral YbDO3A‐like complexes can be used to discriminate chiral α‐hydroxyl acids with a distinct signal difference.