6533b85bfe1ef96bd12bb2de
RESEARCH PRODUCT
Selectivity in the direction of photoisomerization reactions in liquid-crystalline guest-host systems
Herbert MeierThorsten LifkaKlaus Peter Müllersubject
Hydrophobic effectCrystallographyAbsorption spectroscopyPhotoisomerizationLiquid crystalChemistryPhase (matter)MoleculeGeneral ChemistrySelectivityPhotochemistryIsomerizationdescription
E ⇄ Z photoisomerization reactions of stilbenes la-c were studied in liquid-crystalline (LC) phases and in the corresponding isotropic melts. Whereas viscosity has a moderate influence on the photostationary states, a strong effect caused by the regular incorporation of the stilbene molecules in the LC phases was observed. The direction of the isomerization can be reversed, up to the case of a one-way isomerization Z E for the tailored guest-host system 1b/BS. Such an LC-matrix effect is of typical highly ordered (smectic) phases with free volumina which are strictly limited by hydrophobic interactions; it could not be detected in a much more mobile nematic phase. Textures based on the birefringence of doped LC phases, differential-scanning-calorimetry (DSC) measurements and phase-dependent absorption spectra were used for the interpretation.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1995-01-01 | Recueil des Travaux Chimiques des Pays-Bas |