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dc.contributor.authorBolliger, Jeanne L.-
dc.contributor.authorBlacque, Olivier-
dc.contributor.authorFrech, Christian M.-
dc.date.accessioned2018-09-13T06:39:59Z-
dc.date.available2018-09-13T06:39:59Z-
dc.date.issued2008-
dc.identifier.issn0947-6539de_CH
dc.identifier.issn1521-3765de_CH
dc.identifier.urihttps://digitalcollection.zhaw.ch/handle/11475/10510-
dc.description.abstractThe aminophosphine-based pincer complexes [C6H3-2,6-(XP(piperidinyl)2)2Pd(Cl)] (X=NH 1; X=O 2) are readily prepared from cheap starting materials by sequential addition of 1,1',1''-phosphinetriyltripiperidine and 1,3-diaminobenzene or resorcinol to solutions of [Pd(cod)(Cl)2] (cod=cyclooctadiene) in toluene under N2 in "one pot". Compounds 1 and 2 proved to be excellent Heck catalysts and allow the quantitative coupling of several electronically deactivated and sterically hindered aryl bromides with various olefins as coupling partners at 140 degrees C within very short reaction times and low catalyst loadings. Increased reaction temperatures also enable the efficient coupling of olefins with electronically deactivated and sterically hindered aryl chlorides in the presence of only 0.01 mol % of catalyst. The mechanistic studies performed rule out that homogeneous Pd 0 complexes are the catalytically active forms of 1 and 2. On the other hand, the involvement of palladium nanoparticles in the catalytic cycle received strong experimental support. Even though pincer-type Pd IV intermediates derived from 1 (and 2) are not involved in the catalytic cycle of the Heck reaction, their general existence as reactive intermediates (for example, in other reactions) cannot be excluded. On the contrary, they were shown to be thermally accessible. Compounds 1 and 2 show a smooth halide exchange with bromobenzene to yield their bromo derivatives in DMF at 100 degrees C. Experimental observations revealed that the halide exchange most probably proceeded via pincer-type Pd IV intermediates. DFT calculations support this hypothesis and indicated that aminophosphine-based pincer-type Pd IV intermediates are generally to be considered as reactive intermediates in reactions with aryl halides performed at elevated temperatures.de_CH
dc.language.isoende_CH
dc.publisherWileyde_CH
dc.relation.ispartofChemistry - A European Journalde_CH
dc.rightsLicence according to publishing contractde_CH
dc.subject.ddc540: Chemiede_CH
dc.titleRationally designed pincer-type Heck catalysts bearing aminophosphine substituents : PdIV intermediates and palladium nanoparticlesde_CH
dc.typeBeitrag in wissenschaftlicher Zeitschriftde_CH
dcterms.typeTextde_CH
zhaw.departementLife Sciences und Facility Managementde_CH
dc.identifier.doi10.1002/chem.200800441de_CH
dc.identifier.pmid18618875de_CH
zhaw.funding.euNode_CH
zhaw.issue26de_CH
zhaw.originated.zhawNode_CH
zhaw.pages.end7977de_CH
zhaw.pages.start7969de_CH
zhaw.publication.statuspublishedVersionde_CH
zhaw.volume14de_CH
zhaw.publication.reviewPeer review (Publikation)de_CH
Appears in Collections:Publikationen Life Sciences und Facility Management

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