title: A new approach to the chiral separation of novel diazenes.
abstract: Two new types of potential liquid-crystalline azo compounds were synthesized in the form of racemic mixtures and as the individual S enantiomers. Both materials consisting of two substituted aromatic rings in the molecular core and one chiral center at the aliphatic moiety showed mesomorphic behavior. The separation of the R and S enantiomers by chiral high-performance liquid chromatography was unsuccessful when the azo compounds were in their natural E state. However, the irradiation of the compounds in the solution by UV light led to an almost quantitative transition to their Z forms. The chromatographic behavior of the compounds in their Z forms was significantly different, and partial separation of the individual enantiomers on chiral polysaccharide-based stationary phases was obtained. Thus, the proposed procedure represents a novel approach to the enantioseparation of chiral diazenes.
authors.affiliation: Department of Chemistry, Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic.|Department of Analytical Chemistry, Faculty of Chemical Engineering, University of Chemistry and Technology, Prague, Czech Republic.
authors.forename: Terézia
authors.initials: T
authors.lastname: Vojtylová
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, University of Wrocław, Wrocław, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Niezgoda
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, University of Wrocław, Wrocław, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Galewski
authors.affiliation: Department of Chemistry, Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic.
authors.forename: Věra
authors.initials: V
authors.lastname: Hamplová
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Engineering, University of Chemistry and Technology, Prague, Czech Republic.
authors.forename: David
authors.initials: D
authors.lastname: Sýkora
keywords: Azobenzenes; Chiral separation; High-performance liquid chromatography; Liquid-crystalline materials; Photoinduced isomerization