{"id":{"repo_id":"whiterose","oai_identifier":"oai:etheses.whiterose.ac.uk:1018"},"canonical_url":"https://search.dev.ndltd.org/etd/whiterose/oai:etheses.whiterose.ac.uk:1018","repository":{"repo_id":"whiterose","name":"White Rose University Consortium","base_url":"https://etheses.whiterose.ac.uk/cgi/oai2"},"display":{"title":"Spectroscopy, Electrochemistry and Photochemistry of Phenylazonaphthalene Dyes","abstract":"The spectroscopy, electrochemistry and photochemistry of seven 2-(4-R-phenylazo)naphthalene-4,8-disulfonate dyes (R-Span dyes), were studied to report on their structure and reactivity in water. The dyes differ in their structure by only the R substituent attached to the phenyl ring, representing a range of electron-donating and electron-withdrawing substituents; most studies were carried out on OH-Span. A combination of UV/Visible, NMR, Raman and IR spectroscopy together with DFT calculations has shown that the dyes are planar in their stable trans-isomer form. The spectra were found to be sensitive to the R substituent and generally they show good correlations with Hammett σp substituent constants. The structures of OH-Span (pKa = 7.98) and NH2-Span (pKa = 2.88) are pH dependent, and none of the dyes show aggregation at ≤ 3 * 10^-2 mol dm^-3. Spectroelectrochemistry and controlled potential electrolysis studies showed that OH-Span undergoes an irreversible four electron reduction process, where detailed product analysis showed that naphthyl and phenyl fragments of the dye are produced due to azo bond scission; similar results were observed for the other R-Span dyes. Dyes containing electron-donating R substituents are more resistant to reduction, whereas dyes containing electron-withdrawing R substituents are more resistant to oxidation. The stability of the R-Span dyes was assessed by reaction with photoinitiator generated 2-hydroxy-2-propyl radicals to study reductive fading. Time-resolved studies were carried out on OH-Span:photoinitiator solutions and rate constants for electron transfer to produce the dye radical anion and subsequent disproportionation were found to be 6.00 * 10^9 and 5.00 * 10^8 dm^3 mol^-1 s^-1, respectively. The detailed product analysis identified the naphthyl fragment of the dye, which was also observed for other R-Span dyes, indicating that the reduction mechanism occurs via disproportionation resulting in azo bond scission. The R-Span dyes show trans to cis photoisomerisation, and NH2-, OH-, OMe- and NHAc-Span showed complete cis to trans thermal back reactions within ca. 30 ms, 35 μs, 11 days and 1 day, respectively.","abstract_html":"The spectroscopy, electrochemistry and photochemistry of seven 2-(4-R-phenylazo)naphthalene-4,8-disulfonate dyes (R-Span dyes), were studied to report on their structure and reactivity in water. The dyes differ in their structure by only the R substituent attached to the phenyl ring, representing a range of electron-donating and electron-withdrawing substituents; most studies were carried out on OH-Span. A combination of UV/Visible, NMR, Raman and IR spectroscopy together with DFT calculations has shown that the dyes are planar in their stable trans-isomer form. The spectra were found to be sensitive to the R substituent and generally they show good correlations with Hammett σp substituent constants. The structures of OH-Span (pKa = 7.98) and NH2-Span (pKa = 2.88) are pH dependent, and none of the dyes show aggregation at ≤ 3 * 10^-2 mol dm^-3. Spectroelectrochemistry and controlled potential electrolysis studies showed that OH-Span undergoes an irreversible four electron reduction process, where detailed product analysis showed that naphthyl and phenyl fragments of the dye are produced due to azo bond scission; similar results were observed for the other R-Span dyes. Dyes containing electron-donating R substituents are more resistant to reduction, whereas dyes containing electron-withdrawing R substituents are more resistant to oxidation. The stability of the R-Span dyes was assessed by reaction with photoinitiator generated 2-hydroxy-2-propyl radicals to study reductive fading. Time-resolved studies were carried out on OH-Span:photoinitiator solutions and rate constants for electron transfer to produce the dye radical anion and subsequent disproportionation were found to be 6.00 * 10^9 and 5.00 * 10^8 dm^3 mol^-1 s^-1, respectively. The detailed product analysis identified the naphthyl fragment of the dye, which was also observed for other R-Span dyes, indicating that the reduction mechanism occurs via disproportionation resulting in azo bond scission. The R-Span dyes show trans to cis photoisomerisation, and NH2-, OH-, OMe- and NHAc-Span showed complete cis to trans thermal back reactions within ca. 30 ms, 35 μs, 11 days and 1 day, respectively.","abstract_has_math":false,"creators":["Bullivant, Chad Quentin"],"institution":"University of York","degree_name":"Ph.D","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Moore, John N","Lindsay Smith, John R"],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010-07","date_published":"2010-07","updated_at":"2026-07-24T06:03:54Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["uk.bl.ethos.533497"],"render_values":[{"text":"uk.bl.ethos.533497","href":null,"code":true}]}]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Moore, John N","Lindsay Smith, John R"]},{"key":"dc:creator","label":"Author","values":["Bullivant, Chad Quentin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2010-07"]},{"key":"dc:date.issued","label":"Date","values":["2010-07"]},{"key":"dc:publisher.commercial","label":"Dc Publisher Commercial","values":["University of York"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Chemistry (York)"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of York"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://etheses.whiterose.ac.uk/id/eprint/1018/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Ph.D"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["uk.bl.ethos.533497"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://etheses.whiterose.ac.uk/id/eprint/1018/1/C_Q_Bullivant_PhD_thesis.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The spectroscopy, electrochemistry and photochemistry of seven 2-(4-R-phenylazo)naphthalene-4,8-disulfonate dyes (R-Span dyes), were studied to report on their structure and reactivity in water. The dyes differ in their structure by only the R substituent attached to the phenyl ring, representing a range of electron-donating and electron-withdrawing substituents; most studies were carried out on OH-Span. A combination of UV/Visible, NMR, Raman and IR spectroscopy together with DFT calculations has shown that the dyes are planar in their stable trans-isomer form. The spectra were found to be sensitive to the R substituent and generally they show good correlations with Hammett σp substituent constants. The structures of OH-Span (pKa = 7.98) and NH2-Span (pKa = 2.88) are pH dependent, and none of the dyes show aggregation at ≤ 3 * 10^-2 mol dm^-3. Spectroelectrochemistry and controlled potential electrolysis studies showed that OH-Span undergoes an irreversible four electron reduction process, where detailed product analysis showed that naphthyl and phenyl fragments of the dye are produced due to azo bond scission; similar results were observed for the other R-Span dyes. Dyes containing electron-donating R substituents are more resistant to reduction, whereas dyes containing electron-withdrawing R substituents are more resistant to oxidation. The stability of the R-Span dyes was assessed by reaction with photoinitiator generated 2-hydroxy-2-propyl radicals to study reductive fading. Time-resolved studies were carried out on OH-Span:photoinitiator solutions and rate constants for electron transfer to produce the dye radical anion and subsequent disproportionation were found to be 6.00 * 10^9 and 5.00 * 10^8 dm^3 mol^-1 s^-1, respectively. The detailed product analysis identified the naphthyl fragment of the dye, which was also observed for other R-Span dyes, indicating that the reduction mechanism occurs via disproportionation resulting in azo bond scission. The R-Span dyes show trans to cis photoisomerisation, and NH2-, OH-, OMe- and NHAc-Span showed complete cis to trans thermal back reactions within ca. 30 ms, 35 μs, 11 days and 1 day, respectively."]},{"key":"dc:format","label":"Dc Format","values":["text"]},{"key":"dc:title","label":"Title","values":["Spectroscopy, Electrochemistry and Photochemistry of Phenylazonaphthalene Dyes"]}]}],"canonical_facts":{"dc:contributor.advisor":["Moore, John N","Lindsay Smith, John R"],"dc:creator":["Bullivant, Chad Quentin"],"dc:date":["2010-07"],"dc:date.issued":["2010-07"],"dc:description.abstract":["The spectroscopy, electrochemistry and photochemistry of seven 2-(4-R-phenylazo)naphthalene-4,8-disulfonate dyes (R-Span dyes), were studied to report on their structure and reactivity in water. The dyes differ in their structure by only the R substituent attached to the phenyl ring, representing a range of electron-donating and electron-withdrawing substituents; most studies were carried out on OH-Span. A combination of UV/Visible, NMR, Raman and IR spectroscopy together with DFT calculations has shown that the dyes are planar in their stable trans-isomer form. The spectra were found to be sensitive to the R substituent and generally they show good correlations with Hammett σp substituent constants. The structures of OH-Span (pKa = 7.98) and NH2-Span (pKa = 2.88) are pH dependent, and none of the dyes show aggregation at ≤ 3 * 10^-2 mol dm^-3. Spectroelectrochemistry and controlled potential electrolysis studies showed that OH-Span undergoes an irreversible four electron reduction process, where detailed product analysis showed that naphthyl and phenyl fragments of the dye are produced due to azo bond scission; similar results were observed for the other R-Span dyes. Dyes containing electron-donating R substituents are more resistant to reduction, whereas dyes containing electron-withdrawing R substituents are more resistant to oxidation. The stability of the R-Span dyes was assessed by reaction with photoinitiator generated 2-hydroxy-2-propyl radicals to study reductive fading. Time-resolved studies were carried out on OH-Span:photoinitiator solutions and rate constants for electron transfer to produce the dye radical anion and subsequent disproportionation were found to be 6.00 * 10^9 and 5.00 * 10^8 dm^3 mol^-1 s^-1, respectively. The detailed product analysis identified the naphthyl fragment of the dye, which was also observed for other R-Span dyes, indicating that the reduction mechanism occurs via disproportionation resulting in azo bond scission. The R-Span dyes show trans to cis photoisomerisation, and NH2-, OH-, OMe- and NHAc-Span showed complete cis to trans thermal back reactions within ca. 30 ms, 35 μs, 11 days and 1 day, respectively."],"dc:format":["text"],"dc:identifier":["uk.bl.ethos.533497"],"dc:identifier.uri":["https://etheses.whiterose.ac.uk/id/eprint/1018/1/C_Q_Bullivant_PhD_thesis.pdf"],"dc:publisher.commercial":["University of York"],"dc:publisher.department":["Chemistry (York)"],"dc:publisher.institution":["University of York"],"dc:relation.isreferencedby":["https://etheses.whiterose.ac.uk/id/eprint/1018/"],"dc:title":["Spectroscopy, Electrochemistry and Photochemistry of Phenylazonaphthalene Dyes"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["Ph.D"]},"updated_at":"2026-07-24T06:03:54Z"}