Synthesis and utility of electronically diverse polycyclic aromatics

This dissertation examines the synthesis of electronically diverse polycyclic aromatics within discrete molecular regimes and as incorporated into robust conjugated polymers. We have pursued two strategies for obtaining these large aromatics from rather elaborate yet readily available pendant aromatic precursors: electrophilic and oxidative cyclizations. Chapters One and Two describe research directed towards expansion of electrophilic cyclizations that utilize alkyne functionality to construct aromatized systems. Strongly-acidic conditions provide transient cationic intermediates that participate in annulations with adjacent arenes or amides to yield dibenzanthracenes or dioxanthracenes, respectively. In the latter case (Chapter Two), smaller model compounds confirmed this unique reactivity and helped to establish synthetic routes that yield isoquinolines in one synthetic step from aryl carbonyls appended with ortho-substituted alkynes. Chapters Three and Four describe efforts directed towards thiophene-based polycyclic aromatics. Tandem cyclization-polymerizations of pendant thiophenes provide robust electrochromic materials with readily tuneable optical bandgaps. Arenes placed adjacent to the highly-reactive oxidized thienyl moieties force this unique reactivity by biasing the system toward intramolecular cyclization. Chemical and electrochemical studies of related model systems further established the tandem reactivity. The generality of this controlled oxidative cyclization provided several readily-functionalized sulfur-based polycyclics. Using this chemistry, larger molecular and polymeric structures with tailored functionality may allow for a survey of electronic applications such as plastic organic field-effect transistors.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Tovar, John Dayton, 1975-

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/1721.1/8046

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8046