Macromolecular-Multisite Catalysts Obtained by Grafting Diaminoaryl Palladium(ii) Complexes onto a Hyperbranched-Polytriallylsilane Support

Schlenk, Christian; Kleij, Arjan W.; Frey, Holger; Koten, Gerard van

doi:10.1002/1521-3757(20001002)112:19<3587::aid-ange3587>3.0.co;2-0

Cited by 16 publications

(3 citation statements)

References 25 publications

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“…The pure aqua complex S,S-19 was prepared in situ by AgBF 4 -mediated halide abstraction and then used as a catalyst in the palladium-catalyzed aldol condensation reaction of benzaldehyde with methyl isocyanoacetate [50]. Monitoring of the reaction progress by GC indicated that the catalytic performance (turnover number and frequency) compares well with those of related achiral catalysts and is not significantly influenced by the a-methyl substituents in the organopalladium complex [50]. Analysis of the product solution by NMR [12] however revealed only 12% ee (trans isomer).…”

Section: Chiral Ruthenium(ii) and Palladium(ii) Catalystsmentioning

confidence: 99%

“…The optical purity of new organic compounds was determined by chiral HPLC (chiracel OD column, hexane -i-PrOH (2%) as eluent, UV -vis detection), those of known compounds were determined by comparison of the observed values with those of authentic samples. Standard procedures have been used for the catalytic reductive alkylation [23], the palladium-catalyzed aldol condensation [50] and the ruthenium-catalyzed hydrogen transfer reaction [5]. Most of the non-stereoselective syntheses were carried out as described in detail for the corresponding enantiopure compounds and are therefore not mentioned separately.…”

Section: Generalmentioning

confidence: 99%

“…The filtrate was evaporated to dryness to give the cationic catalyst precursor S,S-19 in quantitative yield as an off-white solid. This solid was used in situ for the catalytic experiments [50].…”

Section: Rac/meso-t-bumementioning

confidence: 99%

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Chiral platinum and palladium complexes containing functionalized C2-symmetric bisaminoaryl ‘Pincer’ ligands

Albrecht

Kocks

Spek

et al. 2001

Journal of Organometallic Chemistry

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Dedicated to Professor Jean Normant on the occasion of his 65th anniversary in admiration of his great contribution to the application of organocopper chemistry. AbstractThe synthesis of enantiopure (oxo-functionalized) C 2 -symmetric NCN pincer ligands is described. A key step is the symmetric functionalization of the benzylic positions, which was achieved by enantioselective ketone reduction and subsequent stereoselective substitution protocols. The introduction of a-alkyl substituents has a pronounced effect on the cavity for metal binding. For example, lithiation of the a-ethyl-functionalized pincer ligand afforded mixed (alkyl)(aryl)lithium aggregates rather than dinuclear bis(aryl) lithium [Li(NCN)] 2 species as usually observed for NCN-lithium complexes. Similar effects were established for the (trans)-metalation reaction, which proceeded significantly slower when the steric demand of the a-substituent is increased. The potential of the corresponding enantiopure palladium and ruthenium complexes as enantioselective catalyst has been probed in the asymmetric aldol condensation and hydrogen transfer reactions. The low enantiomeric excess of the products of both reactions indicated that face-discrimination of substrates is not induced by these catalysts and that the chiral information must be located in closer proximity to the metal center.

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Section: Chiral Ruthenium(ii) and Palladium(ii) Catalystsmentioning

confidence: 99%

Section: Generalmentioning

confidence: 99%

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Chiral platinum and palladium complexes containing functionalized C2-symmetric bisaminoaryl ‘Pincer’ ligands

Albrecht

Kocks

Spek

et al. 2001

Journal of Organometallic Chemistry

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Metallorganische Pinzetten-Komplexe von Elementen der Platingruppe: Sensoren, Schalter und Katalysatoren

2001

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Seit den ersten Berichten über Übergangsmetallkomplexe mit Pinzetten‐Liganden in den späten siebziger Jahren haben diese Systeme wegen der ungewöhnlichen Eigenschaften, die das Metallzentrum durch den Pinzetten‐Liganden erhält, zunehmendes Interesse hervorgerufen. Typischerweise enthält ein solcher Ligand einen anionischen Arenring, der an beiden ortho‐Positionen mit Heteroatomsubstituenten, z. B. CH2NR2, CH2PR2 oder CH2SR, substituiert ist. Die Heteroatomsubstituenten koordinieren im Allgemeinen ebenfalls an das Metallzentrum und unterstützen daher die M‐C‐σ‐Bindung. Häufig führt dies zu einer dreizähnigen meridionalen Koordination, bei der zwei Metallacyclen gebildet werden, die sich die M‐C‐Bindung teilen. Detaillierte Studien zur Bildung und zu den Eigenschaften einer großen Vielfalt an Pinzetten‐Komplexen von Elementen der Platingruppe führten sowohl zu einem grundlegenden Verständnis vieler Reaktionen der Organometallchemie als auch zu einer Reihe neuer Anwendungen. Die Entdeckung von Katalysatoren für die Alkandehydrierung, die Aufklärung der Mechanismen bestimmter Basisreaktionen (z. B. der C‐C‐Aktivierung) sowie die Entwicklung der ersten wiederverwendbaren Metallodendrimere als Katalysatoren in der homogenen Katalyse und kristalliner Schalter zur Materialveredelung sind nur einige der vielen Höhepunkte, die aus den vielfältigen Untersuchungen hervorgegangen sind. In dieser Übersicht werden zum einen die Synthesemethoden besprochen, die zurzeit für die Herstellung von Komplexen aus Elementen der Platingruppe und Pinzetten‐Liganden bekannt sind. Zum anderen werden vor allem Anwendungen von Pinzetten‐Komplexen in den Materialwissenschaften, wie die Entwicklung und Veredelung von Sensoren, Schaltern und Katalysatoren, diskutiert.

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Platinum Group Organometallics Based on “Pincer” Complexes: Sensors, Switches, and Catalysts

Albrecht

Koten

2001

Angew. Chem. Int. Ed.

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1,555

819

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Macromolecular-Multisite Catalysts Obtained by Grafting Diaminoaryl Palladium(ii) Complexes onto a Hyperbranched-Polytriallylsilane Support

Cited by 16 publications

References 25 publications

Chiral platinum and palladium complexes containing functionalized C2-symmetric bisaminoaryl ‘Pincer’ ligands

Chiral platinum and palladium complexes containing functionalized C2-symmetric bisaminoaryl ‘Pincer’ ligands

Metallorganische Pinzetten-Komplexe von Elementen der Platingruppe: Sensoren, Schalter und Katalysatoren

Platinum Group Organometallics Based on “Pincer” Complexes: Sensors, Switches, and Catalysts

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