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Updated: Jun 23, 2026

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
Published on: February 7, 2017
Correlation between structures of chiral polymers and their efficiency for chiral resolution by crystallization
Tali Menahem1, Martin Pravda, Yitzhak Mastai
1Department of Chemistry, Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan, Israel.
Abstract:
In this work, we describe the correlation between chiral polymer structures, particularly alpha-helical and random coil conformations, and their efficiency as chiral resolving agents in crystallization processes. A set of chiral block copolymers based on polyethylene oxide with chiral glutamic acid oligopeptide segments (PEG(113)-b-(+)-(S)-Glu(20)) were synthesized and employed as additives in the crystallization of rac-threonine. CD spectroscopy demonstrates that structures of chiral polymers could be switched between a helical and a disordered random coil by pH. The effect of these polymers at different conformations on the crystallization kinetics, crystal morphology, and chiral resolution of rac-threonine is reported. Our study demonstrates that only chiral polymers with alpha-helical conformations of the chiral segment are effective as additives for chiral resolution throughout crystallization. Overall, our results provide useful guidelines for the selection and design of chiral polymer additives that will act efficiently for chiral resolution by crystallization.
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