Preferential Enrichment of Enantiomer from Amino Acid Schiff Bases by Coordination Interaction and Crystallization

Autor: Li Yan, Zhongkui Li, Xue Zhong, Jianxin Du, Yan Xiong, Shaochun Peng, Hui Li
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Materials, Vol 16, Iss 2, p 530 (2023)
Druh dokumentu: article
ISSN: 1996-1944
DOI: 10.3390/ma16020530
Popis: In this paper, preferential enrichment (PE) is described for three pairs of novel amino acid Schiff base Cu(II)/Cu(I) complexes. Single crystal X-ray diffraction indicated that 1-S/R are one-dimensional coordination polymers (CPs) with helical structures, and 2-S/R and 3-S/R are one-dimensional CPs with auxiliary ligands. By tuning the pH, the solvent and second ligands, the 1-S/R, 3-S/R underwent polymorphic transitions, resulting in enantioselective liberation of excess enantiomers into solution, until the deposited crystals were slightly enriched with the opposite enantiomer, thereby successfully exhibiting PE. However, under the effects of Cu(II), the solvent and low pH, 2-S/R did not exhibit PE and resulted in enrichment of racemic compounds, which was attributed to amino acid Schiff base chiral complex mechanisms of PE. The three pairs of Cu complex structures were characterized by UV-vis, MS and X-ray photoelectron spectroscopy (XPS). All chiral properties were studied by circular dichroism (CD) in the solid and liquid.
Databáze: Directory of Open Access Journals
Nepřihlášeným uživatelům se plný text nezobrazuje