Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties

A new series of liquid crystalline compounds comprising a U-shaped unit as central core incorporating azobenzene in the side arms and having terminal alkene functional groups, is synthesized and characterized by differential scanning calorimetry (DSC), polarized-light optical microscopy (POM), X-ray...

Full description

Bibliographic Details
Main Authors:	Lutfor, M. R., Sarkar, Shaheen M., M. M., Yusoff, Kumar, Sandeep, Tschierske, Carsten
Format:	Article
Language:	English
Published:	Royal Society of Chemistry 2015
Subjects:	Q Science (General)
Online Access:	http://umpir.ump.edu.my/id/eprint/11158/ http://umpir.ump.edu.my/id/eprint/11158/ http://umpir.ump.edu.my/id/eprint/11158/ http://umpir.ump.edu.my/id/eprint/11158/1/Synthesis%20of%20New%20U-Shaped%20Azobenzene%20Liquid%20Crystals%20for%20Photoswitching%20Properties.pdf

id	ump-11158
recordtype	eprints
spelling	ump-111582018-02-06T06:38:12Z http://umpir.ump.edu.my/id/eprint/11158/ Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties Lutfor, M. R. Sarkar, Shaheen M. M. M., Yusoff Kumar, Sandeep Tschierske, Carsten Q Science (General) A new series of liquid crystalline compounds comprising a U-shaped unit as central core incorporating azobenzene in the side arms and having terminal alkene functional groups, is synthesized and characterized by differential scanning calorimetry (DSC), polarized-light optical microscopy (POM), X-ray diffraction analysis and UV-vis spectroscopy. In the U-shaped series, all compounds showed stable enantiotropic monolayer SmA phases independent on the chain length and chain parity. These U-shaped molecules exhibit strong photoisomerisation behaviour in solutions and in solid state. The photoswitching properties of compounds showed trans to cis isomerization in about 15 seconds, whereas reverse process required much longer times ranging from 235–380 min in solutions. In case of solid film of 4a, E–Z photoisomerization takes around 4 s and the reverse transformation to original Z–E state takes about 74 min. The kinetic study using UV light irradiation shows that all compounds (4a–e) behave first order rate law throughout the relaxation time in solution. The effect of alkyl chain length for trans to cis is negligible whereas, cis to trans is substantial on the odd–even chain length. The photoisomerization study with variable light intensities shows that the photosaturation and thermal back relaxation times are decreased when intensity of the irradiated light is increased. Compounds did not degrade with light illumination at 10 mW cm−2. The reversible isomerization did not significantly decay after multiple cycles indicating that the photo-responsive properties are stable and repeatable. Thus, the photoswitching behaviour of these materials may be suitably exploited in the field of optical data storage device and in molecular switches for suitable switching times. Royal Society of Chemistry 2015 Article PeerReviewed application/pdf en http://umpir.ump.edu.my/id/eprint/11158/1/Synthesis%20of%20New%20U-Shaped%20Azobenzene%20Liquid%20Crystals%20for%20Photoswitching%20Properties.pdf Lutfor, M. R. and Sarkar, Shaheen M. and M. M., Yusoff and Kumar, Sandeep and Tschierske, Carsten (2015) Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties. RSC Advances, 5 (106). pp. 87019-87029. ISSN 2046-2069 http://dx.doi.org/10.1039/C5RA12705J DOI: 10.1039/C5RA12705J
repository_type	Digital Repository
institution_category	Local University
institution	Universiti Malaysia Pahang
building	UMP Institutional Repository
collection	Online Access
language	English
topic	Q Science (General)
spellingShingle	Q Science (General) Lutfor, M. R. Sarkar, Shaheen M. M. M., Yusoff Kumar, Sandeep Tschierske, Carsten Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties
description	A new series of liquid crystalline compounds comprising a U-shaped unit as central core incorporating azobenzene in the side arms and having terminal alkene functional groups, is synthesized and characterized by differential scanning calorimetry (DSC), polarized-light optical microscopy (POM), X-ray diffraction analysis and UV-vis spectroscopy. In the U-shaped series, all compounds showed stable enantiotropic monolayer SmA phases independent on the chain length and chain parity. These U-shaped molecules exhibit strong photoisomerisation behaviour in solutions and in solid state. The photoswitching properties of compounds showed trans to cis isomerization in about 15 seconds, whereas reverse process required much longer times ranging from 235–380 min in solutions. In case of solid film of 4a, E–Z photoisomerization takes around 4 s and the reverse transformation to original Z–E state takes about 74 min. The kinetic study using UV light irradiation shows that all compounds (4a–e) behave first order rate law throughout the relaxation time in solution. The effect of alkyl chain length for trans to cis is negligible whereas, cis to trans is substantial on the odd–even chain length. The photoisomerization study with variable light intensities shows that the photosaturation and thermal back relaxation times are decreased when intensity of the irradiated light is increased. Compounds did not degrade with light illumination at 10 mW cm−2. The reversible isomerization did not significantly decay after multiple cycles indicating that the photo-responsive properties are stable and repeatable. Thus, the photoswitching behaviour of these materials may be suitably exploited in the field of optical data storage device and in molecular switches for suitable switching times.
format	Article
author	Lutfor, M. R. Sarkar, Shaheen M. M. M., Yusoff Kumar, Sandeep Tschierske, Carsten
author_facet	Lutfor, M. R. Sarkar, Shaheen M. M. M., Yusoff Kumar, Sandeep Tschierske, Carsten
author_sort	Lutfor, M. R.
title	Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties
title_short	Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties
title_full	Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties
title_fullStr	Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties
title_full_unstemmed	Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties
title_sort	synthesis of new u-shaped azobenzene liquid crystals for photoswitching properties
publisher	Royal Society of Chemistry
publishDate	2015
url	http://umpir.ump.edu.my/id/eprint/11158/ http://umpir.ump.edu.my/id/eprint/11158/ http://umpir.ump.edu.my/id/eprint/11158/ http://umpir.ump.edu.my/id/eprint/11158/1/Synthesis%20of%20New%20U-Shaped%20Azobenzene%20Liquid%20Crystals%20for%20Photoswitching%20Properties.pdf
first_indexed	2023-09-18T22:11:37Z
last_indexed	2023-09-18T22:11:37Z
_version_	1777415065505366016

Synthesis of New U-Shaped Azobenzene Liquid Crystals for Photoswitching Properties

Similar Items