Electron-deficient heterofluorene conjugated polymers and small molecules

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dc.contributorRupar, Paul A.
dc.contributorSzulczewski, Gregory J.
dc.contributorStreet, Shane C.
dc.contributorPapish, Elizabeth T.
dc.contributorBao, Yuping
dc.contributor.advisorRupar, Paul A.
dc.contributor.authorCassidy, Stephen Joel
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2019-02-12T14:31:12Z
dc.date.available2019-02-12T14:31:12Z
dc.date.issued2018
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractA series of heterofluorene polymers, containing electron-deficient heteroatoms, were designed for investigation. Indium was first chosen for heteroatom substitution, due to the known Lewis acidity of Group-13 elements, and supermesityl (2,4,6-tri-tert-butylphenyl) was used as a protective substituent to reduce unwanted hydrolysis of indafluorene by sterically protecting the vacant p-orbitals of the indium heteroatom. An indafluorene small molecule was synthesized as a model system; however, 1H NMR analysis showed the compound demonstrated poor stability when exposed to air, so an indafluorene polymer based on this design was not pursued. A novel borafluorene was investigated, featuring an OCO pincer-type ligand as the protective substituent, which stabilizes the boron heteroatom through weak B-O dative bonds. A borafluorene small molecule (BMMP-BF) was synthesized as a model system, and demonstrated robust stability under ambient conditions. Surprisingly, BMMP-BF also exhibited an extraordinarily large Stokes shift, and the cause behind this intriguing optical behavior was investigated. The borafluorene was then functionalized as a monomer and incorporated into two copolymer systems in order to examine the effects that extended conjugation and comonomer electron affinity would have on the optoelectronic properties. Optical characterization showed that both copolymers had a change in their optical behavior, relative to BMMP-BF, as demonstrated by smaller Stokes shifts, and CV analysis revealed that both copolymers possessed low lying LUMOs and narrow optical bandgaps. It is our hope that this research will lead to the development of novel n-type semiconductors. A novel carbazole-based polymer was explored, featuring a cationic ammonium functional group incorporated in the conjugated polymer backbone. A quaternized carbazolium small molecule was synthesized through an intramolecular cyclization mechanism, and served as a model system. The small molecule was characterized by NMR and XRD, and exchange of the counter ion was effectively demonstrated. We intended to synthesize a carbazole polymer and characterize the polymer in a non-ionic state, then quaternize the monomer sub-units during a post-polymerization phase to achieve a carbazolium polyelectrolyte. However, the non-ionic polymer had poor solubility in common organic solvents, which restricted access to the desired polyelectrolyte, and several efforts to form a soluble polymer were ultimately unsuccessful.en_US
dc.format.extent191 p.
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otheru0015_0000001_0003169
dc.identifier.otherCassidy_alatus_0004D_13664
dc.identifier.urihttp://ir.ua.edu/handle/123456789/5352
dc.languageEnglish
dc.language.isoen_US
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectChemistry
dc.titleElectron-deficient heterofluorene conjugated polymers and small moleculesen_US
dc.typethesis
dc.typetext
etdms.degree.departmentUniversity of Alabama. Department of Chemistry and Biochemistry
etdms.degree.disciplineChemistry
etdms.degree.grantorThe University of Alabama
etdms.degree.leveldoctoral
etdms.degree.namePh.D.

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