Publication Date

Fall 2019

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Advisor

David J. Brook

Keywords

Conductivity, Organic Semiconductor, Organic Synthesis, Spintronics, Stable Radical, Verdazyl

Subject Areas

Chemistry

Abstract

Interest in spin polarizing materials and their application in electronic devices in the field of spintronics has been steadily growing in recent years. The development of wholly organic spin polarizing materials has been of particular interest due to the material flexibility, solution processing, synthetic modifiability, and longer spin lifetimes of organics compared to inorganic analogs. One class of organic compounds with significant room for exploration is polyconjugated π systems coupled with stable radicals. We have explored the synthesis of oligothiophenes substituted with verdazyl stable free radicals with differing thiophene chain lengths, through a series of halogenation, borylation, and palladium catalyzed Suzuki-Miyarua coupling reactions. The characterization methods employed include IR, NMR, UV-Vis, ESR, GC/LC-MS, and X-ray crystallography. We have successfully synthesized two novel bisverdazyls with conjugated oligomer spacers and analyzed the magnetism, electrochemical redox potentials, crystal structure, and molecular packing of the aforementioned diradicals. We hope to build on this work by analyzing the bisverdazyls for their magnetoresistance, conductivity, and spin polarization properties. Furthermore, we also plan to synthesize more efficient bisverdazyl conjugated spacers utilizing EDOT units, which promise improved conductivity and spin propagation.

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