The computational and experimental studies of acenes, starphenes and [60]fullerene derivatives is described. Acenes are promising organic semiconductors. Hybrid density functional theory applying a triple-zeta valence basis set (B3LYP/6-311+G**) has been used to approximate the HOMO - LUMO excitation gap in various substituted pentacenes. This technique may, in part, synthetically guide substitution patterns of pentacenes and larger acenes. Previous predictions of an open-shell singlet diradical ground state for acenes larger than hexacene have been reproduced and sulfur substitution has been found to alter the electronic ground state to a closed-shell configuration. Substituents that may engage in non-bonding interactions are not well described by the same DFT model, however these shortcomings can be overcome by implementing an appropriate effective-core potential on carbon atoms.
Like acenes, starphenes are a class of polycyclic aromatic hydrocarbon that exhibit interesting electronic characteristics, though synthetically have not been as widely accessable. The synthesis of a soluble precursor to a substituted [4.4.4]tridecastarphene is described. Upon exposure to an excess of [60]fullerene in the presence of a chemical oxidant, the [4.4.4]tridecastarphene PAH is generated and captured in situ by Diels-Alder cycloaddition of the fullerene. Both syn,syn- and syn,anti- diastereomers of the fullerene trisadduct are generated with the syn,syn- formed as the dominant species. Fullerene pi -- pi interactions are believed to drive the formation of the syn,syn- diastereomer.
Understanding intermolecular interactions is critical to the rational design of organic devices. Both electrically conducting and insulating properties are required for the fabrication of such devices. Among these interactions, pi -- pi and CH -- pi interactions dominate the crystal packing in PAHs. Several [60]fullerene derivatives designed to study CH -- pi interactions by variable temperature NMR (VT-NMR) are described. Diels-Alder cycloadducts of [60]fullerene were generated from substituted o-quinodimethane derivatives to give compounds that may or may not engage in an intramolecular CH -- pi interactions. Evaluation of the rate-constant associated with the first-order transition state of a cyclohexene "boat-to-boat" inversion for each fullerene derivative provides evidence for a CH -- pi interaction estimated to be 0.95 kcal/mol.
","abstract_html":"<p>The computational and experimental studies of acenes, starphenes and [60]fullerene derivatives is described. Acenes are promising organic semiconductors. Hybrid density functional theory applying a triple-zeta valence basis set (B3LYP/6-311+G**) has been used to approximate the HOMO - LUMO excitation gap in various substituted pentacenes. This technique may, in part, synthetically guide substitution patterns of pentacenes and larger acenes. Previous predictions of an open-shell singlet diradical ground state for acenes larger than hexacene have been reproduced and sulfur substitution has been found to alter the electronic ground state to a closed-shell configuration. Substituents that may engage in non-bonding interactions are not well described by the same DFT model, however these shortcomings can be overcome by implementing an appropriate effective-core potential on carbon atoms.</p><p>Like acenes, starphenes are a class of polycyclic aromatic hydrocarbon that exhibit interesting electronic characteristics, though synthetically have not been as widely accessable. The synthesis of a soluble precursor to a substituted [4.4.4]tridecastarphene is described. Upon exposure to an excess of [60]fullerene in the presence of a chemical oxidant, the [4.4.4]tridecastarphene PAH is generated and captured in situ by Diels-Alder cycloaddition of the fullerene. Both syn,syn- and syn,anti- diastereomers of the fullerene trisadduct are generated with the syn,syn- formed as the dominant species. Fullerene pi -- pi interactions are believed to drive the formation of the syn,syn- diastereomer.</p><p>Understanding intermolecular interactions is critical to the rational design of organic devices. Both electrically conducting and insulating properties are required for the fabrication of such devices. Among these interactions, pi -- pi and CH -- pi interactions dominate the crystal packing in PAHs. Several [60]fullerene derivatives designed to study CH -- pi interactions by variable temperature NMR (VT-NMR) are described. Diels-Alder cycloadducts of [60]fullerene were generated from substituted o-quinodimethane derivatives to give compounds that may or may not engage in an intramolecular CH -- pi interactions. Evaluation of the rate-constant associated with the first-order transition state of a cyclohexene "boat-to-boat" inversion for each fullerene derivative provides evidence for a CH -- pi interaction estimated to be 0.95 kcal/mol.</p>","abstract_has_math":false,"creators":["Kopreski, Ryan Paul"],"institution":null,"degree_name":"Doctor of Philosophy","degree_level":"Dissertation","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Glen P Miller"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010-01-01T08:00:00Z","date_published":"2010-01-01T08:00:00Z","updated_at":"2026-07-24T05:22:31Z","subjects":["Chemistry","Organic"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholars.unh.edu/dissertation/599","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Glen P Miller"]},{"key":"dc:creator","label":"Author","values":["Kopreski, Ryan Paul"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry","Organic"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholars.unh.edu/dissertation/599"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The computational and experimental studies of acenes, starphenes and [60]fullerene derivatives is described. Acenes are promising organic semiconductors. Hybrid density functional theory applying a triple-zeta valence basis set (B3LYP/6-311+G**) has been used to approximate the HOMO - LUMO excitation gap in various substituted pentacenes. This technique may, in part, synthetically guide substitution patterns of pentacenes and larger acenes. Previous predictions of an open-shell singlet diradical ground state for acenes larger than hexacene have been reproduced and sulfur substitution has been found to alter the electronic ground state to a closed-shell configuration. Substituents that may engage in non-bonding interactions are not well described by the same DFT model, however these shortcomings can be overcome by implementing an appropriate effective-core potential on carbon atoms.
Like acenes, starphenes are a class of polycyclic aromatic hydrocarbon that exhibit interesting electronic characteristics, though synthetically have not been as widely accessable. The synthesis of a soluble precursor to a substituted [4.4.4]tridecastarphene is described. Upon exposure to an excess of [60]fullerene in the presence of a chemical oxidant, the [4.4.4]tridecastarphene PAH is generated and captured in situ by Diels-Alder cycloaddition of the fullerene. Both syn,syn- and syn,anti- diastereomers of the fullerene trisadduct are generated with the syn,syn- formed as the dominant species. Fullerene pi -- pi interactions are believed to drive the formation of the syn,syn- diastereomer.
Understanding intermolecular interactions is critical to the rational design of organic devices. Both electrically conducting and insulating properties are required for the fabrication of such devices. Among these interactions, pi -- pi and CH -- pi interactions dominate the crystal packing in PAHs. Several [60]fullerene derivatives designed to study CH -- pi interactions by variable temperature NMR (VT-NMR) are described. Diels-Alder cycloadducts of [60]fullerene were generated from substituted o-quinodimethane derivatives to give compounds that may or may not engage in an intramolecular CH -- pi interactions. Evaluation of the rate-constant associated with the first-order transition state of a cyclohexene "boat-to-boat" inversion for each fullerene derivative provides evidence for a CH -- pi interaction estimated to be 0.95 kcal/mol.
"]},{"key":"dc:title","label":"Title","values":["Computational and experimental studies of acenes, starphenes and [60]fullerene derivatives"]}]}],"canonical_facts":{"dc:contributor":["Glen P Miller"],"dc:creator":["Kopreski, Ryan Paul"],"dc:description.abstract":["The computational and experimental studies of acenes, starphenes and [60]fullerene derivatives is described. Acenes are promising organic semiconductors. Hybrid density functional theory applying a triple-zeta valence basis set (B3LYP/6-311+G**) has been used to approximate the HOMO - LUMO excitation gap in various substituted pentacenes. This technique may, in part, synthetically guide substitution patterns of pentacenes and larger acenes. Previous predictions of an open-shell singlet diradical ground state for acenes larger than hexacene have been reproduced and sulfur substitution has been found to alter the electronic ground state to a closed-shell configuration. Substituents that may engage in non-bonding interactions are not well described by the same DFT model, however these shortcomings can be overcome by implementing an appropriate effective-core potential on carbon atoms.
Like acenes, starphenes are a class of polycyclic aromatic hydrocarbon that exhibit interesting electronic characteristics, though synthetically have not been as widely accessable. The synthesis of a soluble precursor to a substituted [4.4.4]tridecastarphene is described. Upon exposure to an excess of [60]fullerene in the presence of a chemical oxidant, the [4.4.4]tridecastarphene PAH is generated and captured in situ by Diels-Alder cycloaddition of the fullerene. Both syn,syn- and syn,anti- diastereomers of the fullerene trisadduct are generated with the syn,syn- formed as the dominant species. Fullerene pi -- pi interactions are believed to drive the formation of the syn,syn- diastereomer.
Understanding intermolecular interactions is critical to the rational design of organic devices. Both electrically conducting and insulating properties are required for the fabrication of such devices. Among these interactions, pi -- pi and CH -- pi interactions dominate the crystal packing in PAHs. Several [60]fullerene derivatives designed to study CH -- pi interactions by variable temperature NMR (VT-NMR) are described. Diels-Alder cycloadducts of [60]fullerene were generated from substituted o-quinodimethane derivatives to give compounds that may or may not engage in an intramolecular CH -- pi interactions. Evaluation of the rate-constant associated with the first-order transition state of a cyclohexene "boat-to-boat" inversion for each fullerene derivative provides evidence for a CH -- pi interaction estimated to be 0.95 kcal/mol.
"],"dc:identifier":["https://scholars.unh.edu/dissertation/599"],"dc:subject":["Chemistry","Organic"],"dc:title":["Computational and experimental studies of acenes, starphenes and [60]fullerene derivatives"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Doctor of Philosophy"]},"updated_at":"2026-07-24T05:22:31Z"}