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Dichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefins

2004Journal article Open access
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dc.contributor.authorMoreira, José
dc.contributor.authorValente, Anabela A.
dc.contributor.authorPillinger, Martyn
dc.contributor.authorNunes, Carla D.
dc.contributor.authorGonçalves, Isabel S.
dc.contributor.authorLopes, Andre D.
dc.contributor.authorRomão, Carlos C.
dc.contributor.authorKuhn, Fritz E.
dc.date.accessioned2013-12-05T15:55:19Z
dc.date.available2013-12-05T15:55:19Z
dc.date.issued2004
dc.date.updated2013-12-04T18:18:35Z
dc.description.abstractThe 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).por
dc.identifier.citationMoreira, 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.por
dc.identifier.doihttp://dx.doi.org/10.1039/B311114H
dc.identifier.issn1144-0546
dc.identifier.otherAUT: JMO01545;
dc.identifier.urihttp://hdl.handle.net/10400.1/3224
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherRSC Publishing - Royal Society of Chemistrypor
dc.titleDichloro and dimethyl dioxomolybdenum(VI)–diazabutadiene complexes as catalysts for the epoxidation of olefinspor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage313por
oaire.citation.issue28
oaire.citation.startPage308por
oaire.citation.titleNew Journal of Chemistrypor
oaire.citation.volume2004por
person.familyNameMoreira
person.familyNameD. Lopes
person.givenNameJosé
person.givenNameAndré
person.identifier2824636
person.identifier.ciencia-idDC11-4E1F-F13F
person.identifier.ciencia-id351E-856A-0300
person.identifier.orcid0000-0001-8481-3436
person.identifier.orcid0000-0002-9702-1216
person.identifier.ridF-3807-2010
person.identifier.ridE-2136-2012
person.identifier.scopus-author-id7201506886
person.identifier.scopus-author-id7201958625
rcaap.rightsopenAccesspor
rcaap.typearticlepor
relation.isAuthorOfPublication644799ac-df06-4840-9f12-52c5b3ff0a76
relation.isAuthorOfPublicationf2f0fe56-e04d-4229-b37b-2b9f1789fe2d
relation.isAuthorOfPublication.latestForDiscovery644799ac-df06-4840-9f12-52c5b3ff0a76

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