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Updated: Aug 13, 2026

Optimization of Crystal Growth for Neutron Macromolecular Crystallography
Published on: March 13, 2021
Preferential enrichment: significant influence of minor molecular modification on the mode of polymorphic transition
Daisuke Fujimoto1, Hiroki Takahashi, Tomomi Ariga
1Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.
Abstract:
The relationship between the molecular structure and the occurrence of Preferential Enrichment, an unusually symmetry-breaking enantiomeric resolution phenomenon observed upon simple recrystallization of a certain kind of racemic crystals from organic solvents, has been investigated with respect to a new series of racemic ammonium sulfonate compounds. Racemic [2-[4-(3-ethoxy-2-hydroxypropoxy)phenylcarbamoyl]ethyl]trimethylammonium p-iodobenzenesulfonate [(+/-)-1a] can show preferential enrichment by simple recrystallization from EtOH, whereas its terminal methoxy and propoxy derivatives [(+/-)-1b and (+/-)-1c] are unable to do so. The influence of such a minor molecular modification on Preferential Enrichment has been rationalized in terms of the change of the mode of polymorphic transition during crystallization, which has been confirmed by in situ ATR-FTIR (ReactIR) spectroscopy in solution and in the solid state and by X-ray crystallographic analysis of their single crystals.
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