Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins
Autor(a) principal: | |
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Data de Publicação: | 2004 |
Outros Autores: | , , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.1/3224 |
Resumo: | The dioxomolybdenum(VI) complex [MoO2Cl2{p-tolyl(CH3DAB)}] has been prepared in good yield by reaction of the solvent adduct MoO2Cl2(THF)2 with one equivalent of the bidentate ligand N,N-p-tolyl-2,3-dimethyl- 1,4-diazabutadiene. Treatment of the dichloro complex with the Grignard reagent CH3MgCl gives the dimethyl derivative [MoO2(CH3)2{p-tolyl(CH3DAB)}]. The complexes are highly active and selective catalysts for the homogeneous epoxidation of cyclooctene using tert-butyl hydroperoxide (TBHP) as the oxidant. In both cases, the initial activity is ca. 175 mol mol 1 Mo h 1 and cyclooctene oxide is obtained quantitatively within 4 h. It was possible to recover the dimethyl complex at the end of the reaction and reuse it in a second run with only a small decrease in activity. The complexes are also active and selective for the epoxidation of other olefins, such as 1-octene, 2-octene, cyclododecene and (R)-(þ)-limonene, with TBHP. The catalytic production of cyclooctene oxide was investigated in detail, varying either the reaction temperature or the initial concentrations of substrate, oxidant and catalyst precursor. Kinetic studies show that the catalyst precursor–oxygen donor complex formation is first-order in TBHP and in the metal complex [MoO2Cl2{p-tolyl(CH3DAB)}]. A specific rate of 3.2 mol 1 dm3 s 1 was found for catalyst formation at 25 C. Activation parameters for this reaction have also been measured (DH6¼ ¼ 48 3 kJ mol 1, DS6¼ ¼ 112 10 J mol 1 K 1). |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefinsThe dioxomolybdenum(VI) complex [MoO2Cl2{p-tolyl(CH3DAB)}] has been prepared in good yield by reaction of the solvent adduct MoO2Cl2(THF)2 with one equivalent of the bidentate ligand N,N-p-tolyl-2,3-dimethyl- 1,4-diazabutadiene. Treatment of the dichloro complex with the Grignard reagent CH3MgCl gives the dimethyl derivative [MoO2(CH3)2{p-tolyl(CH3DAB)}]. The complexes are highly active and selective catalysts for the homogeneous epoxidation of cyclooctene using tert-butyl hydroperoxide (TBHP) as the oxidant. In both cases, the initial activity is ca. 175 mol mol 1 Mo h 1 and cyclooctene oxide is obtained quantitatively within 4 h. It was possible to recover the dimethyl complex at the end of the reaction and reuse it in a second run with only a small decrease in activity. The complexes are also active and selective for the epoxidation of other olefins, such as 1-octene, 2-octene, cyclododecene and (R)-(þ)-limonene, with TBHP. The catalytic production of cyclooctene oxide was investigated in detail, varying either the reaction temperature or the initial concentrations of substrate, oxidant and catalyst precursor. Kinetic studies show that the catalyst precursor–oxygen donor complex formation is first-order in TBHP and in the metal complex [MoO2Cl2{p-tolyl(CH3DAB)}]. A specific rate of 3.2 mol 1 dm3 s 1 was found for catalyst formation at 25 C. Activation parameters for this reaction have also been measured (DH6¼ ¼ 48 3 kJ mol 1, DS6¼ ¼ 112 10 J mol 1 K 1).RSC Publishing - Royal Society of ChemistrySapientiaMoreira, JoséValente, Anabela A.Pillinger, MartynNunes, Carla D.Gonçalves, Isabel S.Lopes, Andre D.Romão, Carlos C.Kuhn, Fritz E.2013-12-05T15:55:19Z20042013-12-04T18:18:35Z2004-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.1/3224engMoreira, José A.; Valente, Anabela A.; Pillinger, Martyn; Nunes, Carla D.; Gonçalves, Isabel S.; Lopes, André D.; Romão, Carlos C.; Kuhn, Fritz E.Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins, New Journal of Chemistry, 2004, 28, 308-313, 2004.1144-0546AUT: JMO01545;http://dx.doi.org/10.1039/B311114Hinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-07-24T10:14:15Zoai:sapientia.ualg.pt:10400.1/3224Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T19:56:50.804813Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins |
title |
Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins |
spellingShingle |
Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins Moreira, José |
title_short |
Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins |
title_full |
Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins |
title_fullStr |
Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins |
title_full_unstemmed |
Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins |
title_sort |
Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins |
author |
Moreira, José |
author_facet |
Moreira, José Valente, Anabela A. Pillinger, Martyn Nunes, Carla D. Gonçalves, Isabel S. Lopes, Andre D. Romão, Carlos C. Kuhn, Fritz E. |
author_role |
author |
author2 |
Valente, Anabela A. Pillinger, Martyn Nunes, Carla D. Gonçalves, Isabel S. Lopes, Andre D. Romão, Carlos C. Kuhn, Fritz E. |
author2_role |
author author author author author author author |
dc.contributor.none.fl_str_mv |
Sapientia |
dc.contributor.author.fl_str_mv |
Moreira, José Valente, Anabela A. Pillinger, Martyn Nunes, Carla D. Gonçalves, Isabel S. Lopes, Andre D. Romão, Carlos C. Kuhn, Fritz E. |
description |
The dioxomolybdenum(VI) complex [MoO2Cl2{p-tolyl(CH3DAB)}] has been prepared in good yield by reaction of the solvent adduct MoO2Cl2(THF)2 with one equivalent of the bidentate ligand N,N-p-tolyl-2,3-dimethyl- 1,4-diazabutadiene. Treatment of the dichloro complex with the Grignard reagent CH3MgCl gives the dimethyl derivative [MoO2(CH3)2{p-tolyl(CH3DAB)}]. The complexes are highly active and selective catalysts for the homogeneous epoxidation of cyclooctene using tert-butyl hydroperoxide (TBHP) as the oxidant. In both cases, the initial activity is ca. 175 mol mol 1 Mo h 1 and cyclooctene oxide is obtained quantitatively within 4 h. It was possible to recover the dimethyl complex at the end of the reaction and reuse it in a second run with only a small decrease in activity. The complexes are also active and selective for the epoxidation of other olefins, such as 1-octene, 2-octene, cyclododecene and (R)-(þ)-limonene, with TBHP. The catalytic production of cyclooctene oxide was investigated in detail, varying either the reaction temperature or the initial concentrations of substrate, oxidant and catalyst precursor. Kinetic studies show that the catalyst precursor–oxygen donor complex formation is first-order in TBHP and in the metal complex [MoO2Cl2{p-tolyl(CH3DAB)}]. A specific rate of 3.2 mol 1 dm3 s 1 was found for catalyst formation at 25 C. Activation parameters for this reaction have also been measured (DH6¼ ¼ 48 3 kJ mol 1, DS6¼ ¼ 112 10 J mol 1 K 1). |
publishDate |
2004 |
dc.date.none.fl_str_mv |
2004 2004-01-01T00:00:00Z 2013-12-05T15:55:19Z 2013-12-04T18:18:35Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10400.1/3224 |
url |
http://hdl.handle.net/10400.1/3224 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Moreira, José A.; Valente, Anabela A.; Pillinger, Martyn; Nunes, Carla D.; Gonçalves, Isabel S.; Lopes, André D.; Romão, Carlos C.; Kuhn, Fritz E.Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins, New Journal of Chemistry, 2004, 28, 308-313, 2004. 1144-0546 AUT: JMO01545; http://dx.doi.org/10.1039/B311114H |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
RSC Publishing - Royal Society of Chemistry |
publisher.none.fl_str_mv |
RSC Publishing - Royal Society of Chemistry |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799133177936084992 |