Discrimination of enantiomeric excess of optically active trifluorolactate by distillation: Evidence for a multi-center hydrogen bonding network in the liquid state

The paper provides evidence for the existence of a multi-center hydrogen bonding network of trifluorolactate, the structure of which was elucidated by single crystal X-ray diffraction analysis, in the liquid state. We reported that the trifluorolactate experienced discrimination of its enantiomeric excess by distillation. X-ray crystallographic analyses of the single crystals of the trifluorolactates suggested that the phenomenon could be caused by a homo-chiral recognizing hydrogen bonding system. Low-angle X-ray diffraction measurement of the trifluorolactate in the liquid state showed a ca. 5 angstrom repeated, which indicates the existence of the hydrogen bonding network in the liquid state. Here, the chiral recognition could be caused by the electrostatic repulsion of the negative charges on trifluoromethyl groups. (C) 2010 Elsevier B.V. All rights reserved.