Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Program Name/Specialization

Biological and Chemical Sciences

Faculty/School

Faculty of Science

First Advisor

Kenneth E. Maly

Advisor Role

Supervisor

Abstract

Abstract

Heterocyclic aromatic compounds represent a versatile class of π-conjugated materials in which heteroatom incorporation enables precise control over electronic structure, photophysical behavior, and solid-state organization. However, a systematic understanding of how molecular topology and conjugation pathways influence these properties remains limited. This dissertation addresses this challenge through the design and synthesis of luminescent heterocyclic aromatic compounds using nucleophilic aromatic substitution (SNAr) and palladium-catalyzed cross-coupling strategies. A modular synthetic platform based on electron-deficient dicyano-functionalized heteroacene building blocks was developed, enabling controlled structural modification and direct evaluation of structure–property relationships. Regioselective iodination of these heteroaromatic cores provided versatile building blocks (3 and 4) for subsequent Sonogashira and Suzuki–Miyaura cross-coupling reactions, allowing systematic π-extension while preserving intrinsic photophysical properties. Using this platform, both star-shaped (11-13) and linear (34-37) π-extended architectures were synthesized to directly evaluate the influence of molecular topology. Photophysical studies reveal that ground-state absorption can be tuned through molecular design, particularly through conjugation pathway and geometry, whereas emission is primarily governed by the intrinsic electronic structure of the heteroaromatic chromophore. The extent to which topology influences excited-state behavior depends strongly on molecular architecture, with star-shaped systems promoting delocalized excited states and enhanced intramolecular charge transfer, while linear systems retain more localized, chromophore-dominated emission. Finally, macrocycle-inspired systems were explored using dynamic covalent concepts, revealing limitations in reversibility within rigid π-conjugated architectures. Overall, this work establishes SNAr chemistry combined with cross-coupling as a powerful modular platform for constructing luminescent heterocyclic materials and identifies molecular topology, conjugation pathway, and chromophore identity as key design parameters governing photophysical behavior. These findings provide guiding principles for the rational design of next-generation π-conjugated materials for optoelectronic applications.

Convocation Year

2026

Convocation Season

Fall

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Available for download on Saturday, June 19, 2027

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