olid-state and liquid-state NMR spectroscopic techniques are used to describe at molecular level the behaviour of a de Vries liquid crystal (namely the mesogen 9HL) at the SmA-SmC* transition, which is characterized by the absence of the layer shrinkage, typical of non-de Vries smectogens. Previous H-2 NMR studies on the same smectogen, performed at a different magnetic field (from 4.70 to 18.80 T), provided evidence of the occurrence of a tilt of one of the three phenyl rings, constituting the aromatic core of 9HL, at the SmA-SmC* phase transition. In this work, the study is extended to the whole rigid aromatic core of the 9HL. In particular, the variable temperature behavior of the mesogen studied by 1D C-13 NMR cross-polarization (CP) and 2D H-1-C-13 PDLF (proton-encoded C-13-detected, local field) NMR experiments made possible the characterization of the conformational and orientational properties in the two smectic phases. These results are compared with various proposed models invoked to describe the SmA-SmC* transition in de Vries smectogens at a molecular level.

Conformational properties and orientational order of a de Vries liquid crystal investigated through NMR spectroscopy / Domenici, Valentina; Lelli, Moreno; Cifelli, Mario; Hamplova, Vera; Marchetti, Alessandro; Veracini, Carlo Alberto. - In: CHEMPHYSCHEM. - ISSN 1439-4235. - STAMPA. - 15:(2014), pp. 1485-1495. [10.1002/cphc.201301036]

Conformational properties and orientational order of a de Vries liquid crystal investigated through NMR spectroscopy

LELLI, MORENO
Methodology
;
2014

Abstract

olid-state and liquid-state NMR spectroscopic techniques are used to describe at molecular level the behaviour of a de Vries liquid crystal (namely the mesogen 9HL) at the SmA-SmC* transition, which is characterized by the absence of the layer shrinkage, typical of non-de Vries smectogens. Previous H-2 NMR studies on the same smectogen, performed at a different magnetic field (from 4.70 to 18.80 T), provided evidence of the occurrence of a tilt of one of the three phenyl rings, constituting the aromatic core of 9HL, at the SmA-SmC* phase transition. In this work, the study is extended to the whole rigid aromatic core of the 9HL. In particular, the variable temperature behavior of the mesogen studied by 1D C-13 NMR cross-polarization (CP) and 2D H-1-C-13 PDLF (proton-encoded C-13-detected, local field) NMR experiments made possible the characterization of the conformational and orientational properties in the two smectic phases. These results are compared with various proposed models invoked to describe the SmA-SmC* transition in de Vries smectogens at a molecular level.
2014
15
1485
1495
Goal 7: Affordable and clean energy
Domenici, Valentina; Lelli, Moreno; Cifelli, Mario; Hamplova, Vera; Marchetti, Alessandro; Veracini, Carlo Alberto
File in questo prodotto:
File Dimensione Formato  
Domenici_et_al-2014-ChemPhysChem.pdf

Accesso chiuso

Descrizione: Articolo principale
Tipologia: Pdf editoriale (Version of record)
Licenza: Tutti i diritti riservati
Dimensione 802.41 kB
Formato Adobe PDF
802.41 kB Adobe PDF   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1086305
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 28
  • ???jsp.display-item.citation.isi??? 28
social impact