Boron Clusters as the Centerpiece of Advanced Liquid Crystals: Fundamental Chemistry and Properties
Liquid crystals incorporating boron clusters are of interest for electro-optics, ion transport, and fundamental structure-property relationship studies. A liquid crystal is a fluid possessing orientational and positional order between that of the lattice of a solid (long-range orientational and long...
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ndltd-VANDERBILT-oai-VANDERBILTETD-etd-03242011-2108422013-01-08T17:16:47Z Boron Clusters as the Centerpiece of Advanced Liquid Crystals: Fundamental Chemistry and Properties Ringstrand, Bryan Scott Chemistry Liquid crystals incorporating boron clusters are of interest for electro-optics, ion transport, and fundamental structure-property relationship studies. A liquid crystal is a fluid possessing orientational and positional order between that of the lattice of a solid (long-range orientational and long-range positional order) and the random disorder (no orientational or positional order) of a liquid. Balance between the rigidity of the molecular core and flexible periphery dictates the type of liquid crystalline phase and its stability. Anisometric molecules, typically rods or discs, form liquid crystalline phases. closo-Boron clusters are inorganic structures characterized by highly delocalized bonding and high chemical, oxidative, and thermal stability. These clusters can exist as highly symmetrical molecules that are either neutral or negatively charged. Within this framework, a negatively charged boron cluster, [closo-1-CB9H10]-, was exploited as the centerpiece of both zwitterionic and ionic liquid crystalline materials. Access to these materials was limited by the lack of synthetic methodology and understanding of reactive intermediates of the [closo-1-CB9H10]- anion. Therefore, a systematic approach was taken to advance the synthetic and physical-organic chemistry of the [closo-1-CB9H10]- anion within the context of incorporating it into liquid crystalline structures. Once this stepwise approach was completed, the newly discovered methodology was employed in the preparation of advanced liquid crystalline materials containing the [closo-1-CB9H10]- anion. Both the zwitterionic and ionic materials were studied for liquid crystalline properties using thermal, optical, and in some cases dielectric and XRD methods. The zwitterionic materials posses large longitudinal dipole moments and were utilized as additives to other liquid crystals, which caused large increases in the dielectric properties of the bulk material. These findings are promising for electro-optical applications. The ionic materials displayed typical liquid crystalline behavior expected for ionic architectures. However, the design of such materials is unique in that the anisometric anion is the driving force behind the organization of the molecules in the fluid phase. These types of materials are promising for photo-physical effects and the potential transport of ions for energy storage or delivery. Piotr Kaszynski Timothy Hanusa Kane Jennings Jeffrey Johnston VANDERBILT 2011-04-06 text application/pdf http://etd.library.vanderbilt.edu/available/etd-03242011-210842/ http://etd.library.vanderbilt.edu/available/etd-03242011-210842/ en restricted I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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Chemistry Ringstrand, Bryan Scott Boron Clusters as the Centerpiece of Advanced Liquid Crystals: Fundamental Chemistry and Properties |
description |
Liquid crystals incorporating boron clusters are of interest for electro-optics, ion transport,
and fundamental structure-property relationship studies. A liquid crystal is a fluid possessing orientational and positional order between that of the lattice of a solid (long-range orientational and long-range positional order) and the random disorder (no orientational or positional order) of a liquid. Balance between the rigidity of the molecular core and flexible periphery dictates the type of liquid crystalline phase and its stability. Anisometric molecules, typically rods or discs, form liquid crystalline phases. closo-Boron clusters are inorganic structures characterized by highly delocalized bonding and high chemical, oxidative, and thermal stability. These clusters can exist as highly
symmetrical molecules that are either neutral or negatively charged.
Within this framework, a negatively charged boron cluster, [closo-1-CB9H10]-, was exploited as the centerpiece of both zwitterionic and ionic liquid crystalline materials. Access to these materials was limited by the lack of synthetic methodology and understanding of reactive intermediates of the [closo-1-CB9H10]- anion. Therefore, a systematic approach was taken to advance the synthetic and physical-organic chemistry of the [closo-1-CB9H10]- anion within the context of incorporating it into liquid crystalline structures. Once this stepwise approach was completed, the newly discovered methodology was employed in the preparation of advanced liquid crystalline materials containing the [closo-1-CB9H10]- anion.
Both the zwitterionic and ionic materials were studied for liquid crystalline
properties using thermal, optical, and in some cases dielectric and XRD methods. The zwitterionic materials posses large longitudinal dipole moments and were utilized as additives to other liquid crystals, which caused large increases in the dielectric properties
of the bulk material. These findings are promising for electro-optical applications. The
ionic materials displayed typical liquid crystalline behavior expected for ionic
architectures. However, the design of such materials is unique in that the anisometric
anion is the driving force behind the organization of the molecules in the fluid phase.
These types of materials are promising for photo-physical effects and the potential transport of ions for energy storage or delivery. |
author2 |
Piotr Kaszynski |
author_facet |
Piotr Kaszynski Ringstrand, Bryan Scott |
author |
Ringstrand, Bryan Scott |
author_sort |
Ringstrand, Bryan Scott |
title |
Boron Clusters as the Centerpiece of Advanced Liquid Crystals: Fundamental Chemistry and Properties |
title_short |
Boron Clusters as the Centerpiece of Advanced Liquid Crystals: Fundamental Chemistry and Properties |
title_full |
Boron Clusters as the Centerpiece of Advanced Liquid Crystals: Fundamental Chemistry and Properties |
title_fullStr |
Boron Clusters as the Centerpiece of Advanced Liquid Crystals: Fundamental Chemistry and Properties |
title_full_unstemmed |
Boron Clusters as the Centerpiece of Advanced Liquid Crystals: Fundamental Chemistry and Properties |
title_sort |
boron clusters as the centerpiece of advanced liquid crystals: fundamental chemistry and properties |
publisher |
VANDERBILT |
publishDate |
2011 |
url |
http://etd.library.vanderbilt.edu/available/etd-03242011-210842/ |
work_keys_str_mv |
AT ringstrandbryanscott boronclustersasthecenterpieceofadvancedliquidcrystalsfundamentalchemistryandproperties |
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