Organic materials with acenoid and iptycene structures

Chapter 1. The synthesis of a group of alkoxy-substituted para-acenequinones and their photophysical properties in solution and liquid crystal are reported. Polarized absorption and fluorescence measurements demonstrate that these acenequinones have excellent alignment with nematic LC hosts, indicating their potential as dichroic dyes for guest-host liquid crystal displays. In addition, the sensitivity of emission to the substitution allows the tuning of emission by functionalization of the acenequinone chromophore. Chapter 2. The synthesis of a series of fluorine- and alkyl/alkoxy-functionalized tetracenes using N-methyl-1,2,4,5-tetrafluoroisoindole as a synthetic building block is reported. The incorporation of fluorine functionalities was found to induce significant face-to-face molecular n-stacking in their crystal structures. Electrochemical behaviors and UV-vis absorbance spectroscopy results of these materials are also discussed. It was demonstrated that the substitution of alkyl/alkoxy groups on the main chain not only provided better solubility in common organic solvents, but also subtly tuned the crystal structures and electrochemical behaviors. Chapter 3. A self-polymerizable AB-type monomer for Diels-Alder (D-A) polymerization was prepared, and its polymerization was carried out in the melt phase and at high pressure in solution. The former method generated only low molecular weight polymer, but the latter one offered an efficient polymerization with increased molecular weight, due to the effect of high-pressure on reactions with a negative activation volume. A pyridinium p-toluenesulfonate catalyzed dehydration reaction of the D-A polymer led to a novel aromatic ladder polymer, poly(iptycene), which is soluble in common organic solvents and stable up to 350 oC.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Chen, Zhihua, Ph. D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Timothy M. Swager.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/41722

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/41722