title: Preferential enrichment: significant influence of minor molecular modification on the mode of polymorphic transition during crystallization.
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.
authors.affiliation: Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Fujimoto
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ariga
authors.forename: Rui
authors.initials: R
authors.lastname: Tamura