English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Deuterium NMR investigation of a discotic mesogen based on hexasubstituted truxene

Sandström, D., Nygren, M., Zimmermann, H., & Maliniak, A. (1995). Deuterium NMR investigation of a discotic mesogen based on hexasubstituted truxene. The Journal of Physical Chemistry A, 99(17), 6661-6669. doi:10.1021/j100017a057.

Item is

Basic

show hide
Genre: Journal Article
Alternative Title : Deuterium NMR investigation of a discotic mesogen based on hexasubstituted truxene

Files

show Files
hide Files
:
JPhysChem_99_1995_6661.pdf (Any fulltext), 142KB
 
File Permalink:
-
Name:
JPhysChem_99_1995_6661.pdf
Description:
-
Visibility:
Restricted (Max Planck Institute for Medical Research, MHMF; )
MIME-Type / Checksum:
application/pdf
Technical Metadata:
Copyright Date:
-
Copyright Info:
-
License:
-

Locators

show
hide
Description:
-
Locator:
https://dx.doi.org/10.1021/j100017a057 (Any fulltext)
Description:
-

Creators

show
hide
 Creators:
Sandström, Dick, Author
Nygren, M., Author
Zimmermann, Herbert1, 2, Author              
Maliniak, Arnold, Author
Affiliations:
1Department of Molecular Physics, Max Planck Institute for Medical Research, Max Planck Society, ou_1497705              
2Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Max Planck Society, ou_1497700              

Content

show
hide
Free keywords: -
 Abstract: We report a 2H nuclear magnetic resonance (NMR) investigation of 2,3,7,8,12,13-hexakis(octadecanoyloxy)- truxene (TxHA17) specifically labeled in the α-position of the alkyl chain. Results from these measurements, together with polarizing microscopy, show that the substance is in a crystalline state up to 90 °C. At this temperature the compound melts and a uniaxial discotic mesophase appears. The liquid crystalline phase persists until the clearing point at 191 "C. The differential scanning calorimetry thermograms confirmed these transitions but exhibited additional peaks below 90 °C. The phase behavior at low temperatures (<90 °C) differs significantly from previous reports by Warmerdam et al. (Liq. Cryst. 1988, 3, 149 and 1087). Solid-state deuterium line shape simulations were used to examine the motions of the labeled methylene site. A Gaussian libration model gave excellent agreement between experimental and calculated 2H NMR spectra. A pronounced spatial inhomogeneity of the motion was found in the high-temperature region of the solid phases. By combining line shape simulations with nuclear spin relaxation measurements, mean correlation times for the α-site could be estimated. It was shown that there exist, even at -100 °C, fast motions of the α-deuterons with rates relatively close to the Larmor frequency. Deuterium NMR spectra of benzene-d6 dissolved in protonated TxHA17 are also reported. These spectra were interpreted using a model in which the benzene molecules occupy two solvation sites: (i) intercalated within the columns of TxHA17 and (ii) dissolved in the aliphatic chains. The exchange of C6D6 between the two sites is slow on the NMR time scale in the crystalline phase whereas it is fast in the mesophase.

Details

show
hide
Language(s): eng - English
 Dates: 1995-01-101994-11-231994-10-231995-04-011995-01-10
 Publication Status: Published in print
 Pages: 1
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: eDoc: 665415
DOI: 10.1021/j100017a057
URI: http://pubs.acs.org/doi/abs/10.1021/j100017a057
Other: 6601
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: The Journal of Physical Chemistry A
  Other : J. Phys. Chem. A
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Columbus, OH : American Chemical Society
Pages: - Volume / Issue: 99 (17) Sequence Number: - Start / End Page: 6661 - 6669 Identifier: ISSN: 1089-5639
CoNE: https://pure.mpg.de/cone/journals/resource/954926947766_4