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Re-entrant isotropic phase between lamellar and columnar mesophases
Urszula Pietrasik1, Jadwiga Szydłowska, Adam Krówczyński
1Chemistry Department, Warsaw University, Laboratory of Dielectrics and Magnetics, Al. Zwirki i Wigury 101, 02-089 Warsaw, Poland.
Journal of the American Chemical Society
|July 26, 2002
Summary
Synthesized nickel (II) complexes with intramolecular hydrogen bonds exhibit unique liquid crystal properties. An isotropic re-entrant phase was observed between columnar and lamellar phases for the first time.
Area of Science:
- Coordination Chemistry
- Materials Science
- Liquid Crystals
Background:
- Tetradental cis-enaminoketone Ni (II) complexes were synthesized.
- Intramolecular hydrogen bonds were introduced to modify molecular structure and properties.
Purpose of the Study:
- To investigate the influence of molecular shape and hydrogen bonding on the liquid crystalline behavior of Ni (II) complexes.
- To explore novel phase sequences in synthesized compounds.
Main Methods:
- Synthesis of tetradental cis-enaminoketone Ni (II) complexes.
- Characterization of molecular structure and phase behavior.
Main Results:
- Complexes with intramolecular hydrogen bonds and alkoxy terminal chains showed an uncommon phase sequence: Iso-D(h)-Iso(re)-SmA.
- The isotropic re-entrant (Iso(re)) phase was observed for the first time, separating columnar (D) and lamellar (SmA) phases.
Conclusions:
- Intramolecular hydrogen bonds significantly impact the mesogenic properties of Ni (II) complexes.
- The discovery of the isotropic re-entrant phase between columnar and lamellar phases offers new insights into liquid crystal phase transitions.
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