Title: Pressure-induced phase transitions on a liquid crystalline europium(III) complex
Authors: Yang, Yuetao ×
Liu, Xiaojun
Nakamura, Arao
Binnemans, Koen
Liu, Jing #
Issue Date: 2008
Publisher: Amer chemical soc
Series Title: Journal of physical chemistry b vol:112 issue:17 pages:5291-5295
Abstract: The effect of pressure on the phase behavior of the liquid crystalline complex [Eu(bta)3L2] (bta is benzoyltrifluoroacetonate, and L is the Schiff base 2-hydroxy-N-octadecyl-4-tetradecyloxybenzaldimine) was studied by X-ray diffraction, Raman spectroscopy, and luminescence spectroscopy. The pressure was varied between ambient pressure and 8.0 GPa. [Eu(bta)3L2] exhibits a smectic A (SmA) phase at room temperature. The complex undergoes a transition from the SmA phase to a solid lamellar structure around 0.22 GPa and another transition from the solid lamellar phase to an amorphous state from 1.6 to 3.5 GPa. At low pressures, the smectic layer spacing increases, and the intermolecular distance decreases. Above 3.5 GPa, both the interlamellar and the intermolecular spacings hardly change, but the intensity of X-ray reflections exhibits a remarkable decrease and eventually vanishes. An interpretation of the changes in the molecular structure is given. It was found that less interdigitation of the alkyl chains situated in adjacent layers and/or a full extension of the alkyl chains occurred at low pressures and that the second phase transition was accompanied by a transfer of the hydrogen atom from the nitrogen atom of the imine group to the oxygen atom of the Schiff base ligand. The effect of applying pressure equals that of the lanthanide contraction on the phase behavior.
ISSN: 1520-6106
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Molecular Design and Synthesis
× corresponding author
# (joint) last author

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