{"id":{"repo_id":"ottawa-retro","oai_identifier":"oai:ruor.uottawa.ca:10393/6059"},"canonical_url":"https://search.dev.ndltd.org/etd/ottawa-retro/oai:ruor.uottawa.ca:10393/6059","repository":{"repo_id":"ottawa-retro","name":"University of Ottawa","base_url":"https://ruor.uottawa.ca/server/oai/request"},"display":{"title":"Chemistry of low and medium-valent niobium complexes supported by anionic amides.","abstract":"Reaction of [NbCl3(TMEDA)]2 with LDA in a stoichiometric ratio of 1:3 Nb/Lithium amide, resulted in a new diamagnetic niobium (II) cluster (TMEDA)3Nb2Cl5Li (2.1) with a very short Nb≡Nb bond. Similarly, reaction of NbCl4(THF) 2 with 2 equiv. of Cy2NLi caused the reduction of the metal center to produce a diamagnetic and tetranuclear cluster, [Nb4Cl 12Li2(THF)8] (2.2). Further reaction of [NbCl3(TMEDA)]2 or (TMEDA)3Nb2Cl 5Li (2.1) with (3,5-Me2Ph)(Ad)NLi in THF yielded the tetravalent, dinuclear and diamagnetic {[(3,5-Me2Ph)(Ad)N]Nb(3,5Me 2Ph)}2(mu-NAd)2.2(ether) (2.3). In the reaction of Nb2Cl6(TMEDA)2 with azobenzene cleavage of the N=N bond results in the formation of the niobium imido complex, NbCl3(C6H5N)(TMEDA) (2.4). The reaction of Nb2Cl6(TMEDA)2 with the potassium salt of tripyrrolylmethane in a 1:1 ratio afforded two products which have been isolated and characterized. The first compound is the dinuclear {[H-C(C4H3N)3]Nb(THF)}2 •2THF (3.1) with two trivalent and diamagnetic metals bridged by two tripyrrolyl trianions. The second product of the reaction is {([H-C(C 4H3N)3]2NbK)2}{Nb4 Cl11[K(THF)2]2}•2THF (3.2 ) which displays some unusual features. The complex is ionic with the cationic {Nb4Cl11[K (THF)2]2} 2+ unit containing the metal in a mixed valence state and the cationic moiety are balanced by two identical anionic {([H-C(C4H3N) 3]2NbK)2}- units each containing Nb in the tetravalent state. A similar reaction carried out with the lithium salt of the tripyrrolide anion led instead to a monomeric tetravalent {[H-C(C 4H3N)3]2Nb}{Li (THF)4} 2 (3.3) complex. Reaction of Nb2Cl5Li(TMEDA)3 with Ph 2NK in THF afforded a complex reaction from which three complex were isolated and characterized. The first compound Cl2Nb 2(mu-Cl)3(TMEDA)2 (4.1) was obtained in analytically pure form as dark purple, paramagnetic and moderately air-sensitive crystals. The second compound is a trivalent and dinuclear {[(Ph2N) 2Nb]2[mu-NPh(mu-eta1:eta2-C 6H4)](mu-H)}{Li(TMEDA)2}.toluene (4.2 ) which was formed via oxidative addition of the two Nb(II) centers to the C--H sigma-bond of one aromatic ring. This species thermally rearranges into the dinuclear and diamagnetic (Ph2N) 2Nb{[mu-NPh(eta6-C6H5)] 2Nb}.ether (4.3). (Abstract shortened by UMI.)","abstract_html":"Reaction of [NbCl3(TMEDA)]2 with LDA in a stoichiometric ratio of 1:3 Nb/Lithium amide, resulted in a new diamagnetic niobium (II) cluster (TMEDA)3Nb2Cl5Li (2.1) with a very short Nb≡Nb bond. Similarly, reaction of NbCl4(THF) 2 with 2 equiv. of Cy2NLi caused the reduction of the metal center to produce a diamagnetic and tetranuclear cluster, [Nb4Cl 12Li2(THF)8] (2.2). Further reaction of [NbCl3(TMEDA)]2 or (TMEDA)3Nb2Cl 5Li (2.1) with (3,5-Me2Ph)(Ad)NLi in THF yielded the tetravalent, dinuclear and diamagnetic {[(3,5-Me2Ph)(Ad)N]Nb(3,5Me 2Ph)}2(mu-NAd)2.2(ether) (2.3). In the reaction of Nb2Cl6(TMEDA)2 with azobenzene cleavage of the N=N bond results in the formation of the niobium imido complex, NbCl3(C6H5N)(TMEDA) (2.4). The reaction of Nb2Cl6(TMEDA)2 with the potassium salt of tripyrrolylmethane in a 1:1 ratio afforded two products which have been isolated and characterized. The first compound is the dinuclear {[H-C(C4H3N)3]Nb(THF)}2 •2THF (3.1) with two trivalent and diamagnetic metals bridged by two tripyrrolyl trianions. The second product of the reaction is {([H-C(C 4H3N)3]2NbK)2}{Nb4 Cl11[K(THF)2]2}•2THF (3.2 ) which displays some unusual features. The complex is ionic with the cationic {Nb4Cl11[K (THF)2]2} 2+ unit containing the metal in a mixed valence state and the cationic moiety are balanced by two identical anionic {([H-C(C4H3N) 3]2NbK)2}- units each containing Nb in the tetravalent state. A similar reaction carried out with the lithium salt of the tripyrrolide anion led instead to a monomeric tetravalent {[H-C(C 4H3N)3]2Nb}{Li (THF)4} 2 (3.3) complex. Reaction of Nb2Cl5Li(TMEDA)3 with Ph 2NK in THF afforded a complex reaction from which three complex were isolated and characterized. The first compound Cl2Nb 2(mu-Cl)3(TMEDA)2 (4.1) was obtained in analytically pure form as dark purple, paramagnetic and moderately air-sensitive crystals. The second compound is a trivalent and dinuclear {[(Ph2N) 2Nb]2[mu-NPh(mu-eta1:eta2-C 6H4)](mu-H)}{Li(TMEDA)2}.toluene (4.2 ) which was formed via oxidative addition of the two Nb(II) centers to the C--H sigma-bond of one aromatic ring. This species thermally rearranges into the dinuclear and diamagnetic (Ph2N) 2Nb{[mu-NPh(eta6-C6H5)] 2Nb}.ether (4.3). (Abstract shortened by UMI.)","abstract_has_math":false,"creators":["Tayebani, Maryam."],"institution":"University of Ottawa (Canada)","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Gambarotta, Sandro,"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2009,"date_issued":"2009-03-23T12:59:20Z","date_published":"2009-03-23T12:59:20Z","updated_at":"2026-07-24T03:39:38Z","subjects":["Chemistry, Inorganic."],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["Source: Dissertation Abstracts International, Volume: 63-05, Section: B, page: 2384.","9780612680043","http://dx.doi.org/10.20381/ruor-11074"],"render_values":[{"text":"Source: Dissertation Abstracts International, Volume: 63-05, Section: B, page: 2384.","href":null,"code":true},{"text":"9780612680043","href":null,"code":true},{"text":"http://dx.doi.org/10.20381/ruor-11074","href":"http://dx.doi.org/10.20381/ruor-11074","code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10393/6059","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gambarotta, Sandro,"]},{"key":"dc:creator","label":"Author","values":["Tayebani, Maryam."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2009-03-23T12:59:20Z","2001"]},{"key":"dc:publisher","label":"Institution","values":["University of Ottawa (Canada)"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Inorganic."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["Source: Dissertation Abstracts International, Volume: 63-05, Section: B, page: 2384.","9780612680043","http://hdl.handle.net/10393/6059","http://dx.doi.org/10.20381/ruor-11074"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Reaction of [NbCl3(TMEDA)]2 with LDA in a stoichiometric ratio of 1:3 Nb/Lithium amide, resulted in a new diamagnetic niobium (II) cluster (TMEDA)3Nb2Cl5Li (2.1) with a very short Nb≡Nb bond. Similarly, reaction of NbCl4(THF) 2 with 2 equiv. of Cy2NLi caused the reduction of the metal center to produce a diamagnetic and tetranuclear cluster, [Nb4Cl 12Li2(THF)8] (2.2). Further reaction of [NbCl3(TMEDA)]2 or (TMEDA)3Nb2Cl 5Li (2.1) with (3,5-Me2Ph)(Ad)NLi in THF yielded the tetravalent, dinuclear and diamagnetic {[(3,5-Me2Ph)(Ad)N]Nb(3,5Me 2Ph)}2(mu-NAd)2.2(ether) (2.3). In the reaction of Nb2Cl6(TMEDA)2 with azobenzene cleavage of the N=N bond results in the formation of the niobium imido complex, NbCl3(C6H5N)(TMEDA) (2.4). The reaction of Nb2Cl6(TMEDA)2 with the potassium salt of tripyrrolylmethane in a 1:1 ratio afforded two products which have been isolated and characterized. The first compound is the dinuclear {[H-C(C4H3N)3]Nb(THF)}2 •2THF (3.1) with two trivalent and diamagnetic metals bridged by two tripyrrolyl trianions. The second product of the reaction is {([H-C(C 4H3N)3]2NbK)2}{Nb4 Cl11[K(THF)2]2}•2THF (3.2 ) which displays some unusual features. The complex is ionic with the cationic {Nb4Cl11[K (THF)2]2} 2+ unit containing the metal in a mixed valence state and the cationic moiety are balanced by two identical anionic {([H-C(C4H3N) 3]2NbK)2}- units each containing Nb in the tetravalent state. A similar reaction carried out with the lithium salt of the tripyrrolide anion led instead to a monomeric tetravalent {[H-C(C 4H3N)3]2Nb}{Li (THF)4} 2 (3.3) complex. Reaction of Nb2Cl5Li(TMEDA)3 with Ph 2NK in THF afforded a complex reaction from which three complex were isolated and characterized. The first compound Cl2Nb 2(mu-Cl)3(TMEDA)2 (4.1) was obtained in analytically pure form as dark purple, paramagnetic and moderately air-sensitive crystals. The second compound is a trivalent and dinuclear {[(Ph2N) 2Nb]2[mu-NPh(mu-eta1:eta2-C 6H4)](mu-H)}{Li(TMEDA)2}.toluene (4.2 ) which was formed via oxidative addition of the two Nb(II) centers to the C--H sigma-bond of one aromatic ring. This species thermally rearranges into the dinuclear and diamagnetic (Ph2N) 2Nb{[mu-NPh(eta6-C6H5)] 2Nb}.ether (4.3). (Abstract shortened by UMI.)"]},{"key":"dc:format","label":"Dc Format","values":["207 p.","application/pdf"]},{"key":"dc:title","label":"Title","values":["Chemistry of low and medium-valent niobium complexes supported by anionic amides."]}]}],"canonical_facts":{"dc:contributor":["Gambarotta, Sandro,"],"dc:creator":["Tayebani, Maryam."],"dc:date":["2009-03-23T12:59:20Z","2001"],"dc:description":["Reaction of [NbCl3(TMEDA)]2 with LDA in a stoichiometric ratio of 1:3 Nb/Lithium amide, resulted in a new diamagnetic niobium (II) cluster (TMEDA)3Nb2Cl5Li (2.1) with a very short Nb≡Nb bond. Similarly, reaction of NbCl4(THF) 2 with 2 equiv. of Cy2NLi caused the reduction of the metal center to produce a diamagnetic and tetranuclear cluster, [Nb4Cl 12Li2(THF)8] (2.2). Further reaction of [NbCl3(TMEDA)]2 or (TMEDA)3Nb2Cl 5Li (2.1) with (3,5-Me2Ph)(Ad)NLi in THF yielded the tetravalent, dinuclear and diamagnetic {[(3,5-Me2Ph)(Ad)N]Nb(3,5Me 2Ph)}2(mu-NAd)2.2(ether) (2.3). In the reaction of Nb2Cl6(TMEDA)2 with azobenzene cleavage of the N=N bond results in the formation of the niobium imido complex, NbCl3(C6H5N)(TMEDA) (2.4). The reaction of Nb2Cl6(TMEDA)2 with the potassium salt of tripyrrolylmethane in a 1:1 ratio afforded two products which have been isolated and characterized. The first compound is the dinuclear {[H-C(C4H3N)3]Nb(THF)}2 •2THF (3.1) with two trivalent and diamagnetic metals bridged by two tripyrrolyl trianions. The second product of the reaction is {([H-C(C 4H3N)3]2NbK)2}{Nb4 Cl11[K(THF)2]2}•2THF (3.2 ) which displays some unusual features. The complex is ionic with the cationic {Nb4Cl11[K (THF)2]2} 2+ unit containing the metal in a mixed valence state and the cationic moiety are balanced by two identical anionic {([H-C(C4H3N) 3]2NbK)2}- units each containing Nb in the tetravalent state. A similar reaction carried out with the lithium salt of the tripyrrolide anion led instead to a monomeric tetravalent {[H-C(C 4H3N)3]2Nb}{Li (THF)4} 2 (3.3) complex. Reaction of Nb2Cl5Li(TMEDA)3 with Ph 2NK in THF afforded a complex reaction from which three complex were isolated and characterized. The first compound Cl2Nb 2(mu-Cl)3(TMEDA)2 (4.1) was obtained in analytically pure form as dark purple, paramagnetic and moderately air-sensitive crystals. The second compound is a trivalent and dinuclear {[(Ph2N) 2Nb]2[mu-NPh(mu-eta1:eta2-C 6H4)](mu-H)}{Li(TMEDA)2}.toluene (4.2 ) which was formed via oxidative addition of the two Nb(II) centers to the C--H sigma-bond of one aromatic ring. This species thermally rearranges into the dinuclear and diamagnetic (Ph2N) 2Nb{[mu-NPh(eta6-C6H5)] 2Nb}.ether (4.3). (Abstract shortened by UMI.)"],"dc:format":["207 p.","application/pdf"],"dc:identifier":["Source: Dissertation Abstracts International, Volume: 63-05, Section: B, page: 2384.","9780612680043","http://hdl.handle.net/10393/6059","http://dx.doi.org/10.20381/ruor-11074"],"dc:publisher":["University of Ottawa (Canada)"],"dc:subject":["Chemistry, Inorganic."],"dc:title":["Chemistry of low and medium-valent niobium complexes supported by anionic amides."],"dc:type":["Thesis"]},"updated_at":"2026-07-24T03:39:38Z"}