Structural and Orientational Properties of the Ferro, Antiferroelectric, and Re-entrant Smectic C Phases of ZLL7/ by Deuterium NMR and Other Experimental Techniques

In this work, two selectively deuterium-labeled isotopomers of the (S)-2-methylbutyl- [4‘-(4‘ ‘-heptyloxyphenyl)-benzoyl-4-oxy-(S)-2-((S)-2‘)-benzoyl)-propionyl)]-propionate (ZLL 7/*), one labeled on the phenyl ring (ZLL 7/ *-phe-D2) and the other one on the biphenyl fragment (ZLL 7/ *-biphe-D2), ha...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:The journal of physical chemistry. B 2006-08, Vol.110 (33), p.16459-16470
Hauptverfasser: Catalano, Donata, Domenici, Valentina, Marini, Alberto, Veracini, Carlo Alberto, Bubnov, Alexej, Glogarová, Milada
Format: Artikel
Sprache:eng
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:In this work, two selectively deuterium-labeled isotopomers of the (S)-2-methylbutyl- [4‘-(4‘ ‘-heptyloxyphenyl)-benzoyl-4-oxy-(S)-2-((S)-2‘)-benzoyl)-propionyl)]-propionate (ZLL 7/*), one labeled on the phenyl ring (ZLL 7/ *-phe-D2) and the other one on the biphenyl fragment (ZLL 7/ *-biphe-D2), have been investigated by deuterium NMR (DNMR) spectroscopy and other experimental techniques. These compounds possess the paraelectric SmA, the ferroelectric SmC*, the antiferroelectric SmC* A, the re-entrant ferroelectric SmC* re, and the ferroelectric hexatic phases down to room temperature. The orientational ordering properties of the two labeled fragments have been determined by means of DNMR, and the mesophase behavior at two magnetic fields is discussed. In particular, the effect of the magnetic field on the supramolecular structure of the SmC* and SmC*re phases is commented. This study revealed to be useful to understand the structural and conformational properties of the ferroelectric/antiferroelectric/re-entrant/hexatic smectic phases. Mesomorphic properties, spontaneous tilt angle, polarization, and layer spacing have been studied for the labeled materials and compared with those obtained for the nonlabeled compound. The two self-consistent set of data, from optical and DNMR measurements and X-ray results, allow us to associate at the transition from the SmC* to the SmC*A phase a change of the molecular conformation.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp0621777