{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/29176"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/29176","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Chromatography and purification of endohedral metallofullerenes","abstract":"At the conception of this research, a separation methodology for obtaining purified mctallofullerene [A<sub>m</sub>@C<sub>2n</sub>, m = # of metal atoms, A, and C<sub>2n</sub> = # of carbons in the surrounding cage] samples was not yet developed. Isolation of these metal-encapsulated fullerenes was strongly desired for characterization of their physical and chemical properties. Predicted applications for these novel species include their use as possible superconductors, catalysts, and non-linear optical devices. However, initial purification efforts have been hindered by several difficulties. These factors include a low abundance (< 1%) in the raw extract, uncertain stability in aerobic environments, co-elution of A<sub>m</sub>@C<sub>2n</sub> with empty-cage fullerenes, and the need for selective chromatographic detection. In this research, these difficulties have been overcome with the development of a continuous-flow, on-line HPLC-EPR apparatus. Advantages include a selective, non-invasive detector with chromatographic separations being performed in a controlled anaerobic environment. This on-line approach permits the selective detection of only those metallofullerenes with an odd-number of encapsulated atoms. The ability to continually monitor separations of these paramagnetic species ultimately permits the optimization of chromatographic parameters. The methodology developed from this on-line HPLC-EPR approach has ultimately resulted in purified empty-cage (C₆₀, C₇₀...C₉₆) and metallofullerene samples (Sc₂@C₇₄, Sc₂@C₇₆, Sc₂@C₇₈, Sc₂@C₈₀, Sc₂@C₈₂, Sc₂@C₈₄ - two isomers, Sc₂@C₈₆, Sc₂@C₈₈, Sc₂@C₉₀, Sc₃@C₈₂, Sc₄@C₈₂, La₂@C₇₂, Er@C₈₂, Er₂@C₈₂ - two isomers, and Er₂@C₉₂).","abstract_html":"At the conception of this research, a separation methodology for obtaining purified mctallofullerene [A&lt;sub&gt;m&lt;/sub&gt;@C&lt;sub&gt;2n&lt;/sub&gt;, m = # of metal atoms, A, and C&lt;sub&gt;2n&lt;/sub&gt; = # of carbons in the surrounding cage] samples was not yet developed. Isolation of these metal-encapsulated fullerenes was strongly desired for characterization of their physical and chemical properties. Predicted applications for these novel species include their use as possible superconductors, catalysts, and non-linear optical devices. However, initial purification efforts have been hindered by several difficulties. These factors include a low abundance (&lt; 1%) in the raw extract, uncertain stability in aerobic environments, co-elution of A&lt;sub&gt;m&lt;/sub&gt;@C&lt;sub&gt;2n&lt;/sub&gt; with empty-cage fullerenes, and the need for selective chromatographic detection. In this research, these difficulties have been overcome with the development of a continuous-flow, on-line HPLC-EPR apparatus. Advantages include a selective, non-invasive detector with chromatographic separations being performed in a controlled anaerobic environment. This on-line approach permits the selective detection of only those metallofullerenes with an odd-number of encapsulated atoms. The ability to continually monitor separations of these paramagnetic species ultimately permits the optimization of chromatographic parameters. The methodology developed from this on-line HPLC-EPR approach has ultimately resulted in purified empty-cage (C₆₀, C₇₀...C₉₆) and metallofullerene samples (Sc₂@C₇₄, Sc₂@C₇₆, Sc₂@C₇₈, Sc₂@C₈₀, Sc₂@C₈₂, Sc₂@C₈₄ - two isomers, Sc₂@C₈₆, Sc₂@C₈₈, Sc₂@C₉₀, Sc₃@C₈₂, Sc₄@C₈₂, La₂@C₇₂, Er@C₈₂, Er₂@C₈₂ - two isomers, and Er₂@C₉₂).","abstract_has_math":false,"creators":["Stevenson, Steven A."],"institution":"Virginia Tech","degree_name":"Ph. D.","degree_level":"doctoral","degree_discipline":"Chemistry","degree_department":"Chemistry","school":null,"contributors":[],"advisors":[],"committee_chairs":["Dorn, Harry C."],"committee_members":["Anderson, Mark R.","Brewer, Karen J.","Taylor, Larry T.","Bell, Harold M."],"year":1995,"date_issued":"1995","date_published":"1995","updated_at":"2026-07-22T22:18:44Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-10032005-171425"],"render_values":[{"text":"etd-10032005-171425","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/29176","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Dorn, Harry C."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Anderson, Mark R.","Brewer, Karen J.","Taylor, Larry T.","Bell, Harold M."]},{"key":"dc:contributor.department","label":"Department","values":["Chemistry"]},{"key":"dc:creator","label":"Author","values":["Stevenson, Steven A."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:17:02Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:17:02Z","2005-10-03"]},{"key":"dc:date.issued","label":"Date","values":["1995"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. 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Isolation of these metal-encapsulated fullerenes was strongly desired for characterization of their physical and chemical properties. Predicted applications for these novel species include their use as possible superconductors, catalysts, and non-linear optical devices. However, initial purification efforts have been hindered by several difficulties. These factors include a low abundance (< 1%) in the raw extract, uncertain stability in aerobic environments, co-elution of A<sub>m</sub>@C<sub>2n</sub> with empty-cage fullerenes, and the need for selective chromatographic detection. In this research, these difficulties have been overcome with the development of a continuous-flow, on-line HPLC-EPR apparatus. Advantages include a selective, non-invasive detector with chromatographic separations being performed in a controlled anaerobic environment. This on-line approach permits the selective detection of only those metallofullerenes with an odd-number of encapsulated atoms. The ability to continually monitor separations of these paramagnetic species ultimately permits the optimization of chromatographic parameters. The methodology developed from this on-line HPLC-EPR approach has ultimately resulted in purified empty-cage (C₆₀, C₇₀...C₉₆) and metallofullerene samples (Sc₂@C₇₄, Sc₂@C₇₆, Sc₂@C₇₈, Sc₂@C₈₀, Sc₂@C₈₂, Sc₂@C₈₄ - two isomers, Sc₂@C₈₆, Sc₂@C₈₈, Sc₂@C₉₀, Sc₃@C₈₂, Sc₄@C₈₂, La₂@C₇₂, Er@C₈₂, Er₂@C₈₂ - two isomers, and Er₂@C₉₂)."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph. D."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["BTD"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Chromatography and purification of endohedral metallofullerenes"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Dorn, Harry C."],"dc:contributor.committeemember":["Anderson, Mark R.","Brewer, Karen J.","Taylor, Larry T.","Bell, Harold M."],"dc:contributor.department":["Chemistry"],"dc:creator":["Stevenson, Steven A."],"dc:date.accessioned":["2014-03-14T20:17:02Z"],"dc:date.available":["2014-03-14T20:17:02Z","2005-10-03"],"dc:date.issued":["1995"],"dc:description.abstract":["At the conception of this research, a separation methodology for obtaining purified mctallofullerene [A<sub>m</sub>@C<sub>2n</sub>, m = # of metal atoms, A, and C<sub>2n</sub> = # of carbons in the surrounding cage] samples was not yet developed. Isolation of these metal-encapsulated fullerenes was strongly desired for characterization of their physical and chemical properties. Predicted applications for these novel species include their use as possible superconductors, catalysts, and non-linear optical devices. However, initial purification efforts have been hindered by several difficulties. These factors include a low abundance (< 1%) in the raw extract, uncertain stability in aerobic environments, co-elution of A<sub>m</sub>@C<sub>2n</sub> with empty-cage fullerenes, and the need for selective chromatographic detection. In this research, these difficulties have been overcome with the development of a continuous-flow, on-line HPLC-EPR apparatus. Advantages include a selective, non-invasive detector with chromatographic separations being performed in a controlled anaerobic environment. This on-line approach permits the selective detection of only those metallofullerenes with an odd-number of encapsulated atoms. The ability to continually monitor separations of these paramagnetic species ultimately permits the optimization of chromatographic parameters. The methodology developed from this on-line HPLC-EPR approach has ultimately resulted in purified empty-cage (C₆₀, C₇₀...C₉₆) and metallofullerene samples (Sc₂@C₇₄, Sc₂@C₇₆, Sc₂@C₇₈, Sc₂@C₈₀, Sc₂@C₈₂, Sc₂@C₈₄ - two isomers, Sc₂@C₈₆, Sc₂@C₈₈, Sc₂@C₉₀, Sc₃@C₈₂, Sc₄@C₈₂, La₂@C₇₂, Er@C₈₂, Er₂@C₈₂ - two isomers, and Er₂@C₉₂)."],"dc:description.degree":["Ph. D."],"dc:format.medium":["BTD"],"dc:format.mimetype":["application/pdf"],"dc:identifier.other":["etd-10032005-171425"],"dc:identifier.uri":["http://hdl.handle.net/10919/29176"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Chromatography and purification of endohedral metallofullerenes"],"dc:type":["Dissertation"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Chemistry"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Ph. D."],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:18:44Z"}