Grafted lanthanide amides: Versatile catalysts for various transformations

Gauvin, Régis M.; Chenal, Thomas; Hassan, Rahma Ali; Addad, Ahmed; Mortreux, André

doi:10.1016/j.molcata.2006.04.022

Cited by 37 publications

(36 citation statements)

References 53 publications

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“…Materials: Tetraalkyl aluminates are major building blocks in organometallic synthesis,45 and are commonly used as co‐catalysts in olefin polymerization processes 19. Among them, we selected lithium tetraalkyl aluminate (Li[Al(CH 3 ) 3 (CH 2 Si(CH 3 ) 3 )]) as a model compound for the S‐RESPDOR experiment.…”

Section: Methodsmentioning

confidence: 99%

Measurement of Aluminum–Carbon Distances Using S‐RESPDOR NMR Experiments

et al. 2012

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It is demonstrated that reliable aluminum-carbon distances can be measured in samples with (13)C natural abundance by NMR spectroscopy. Overcoupled resonators, with only one radio-frequency synthesizer and one amplifier, are used to irradiate in the same pulse sequence (27)Al and (13)C nuclei, which differ by only 3.6 % in Larmor frequencies. The combination of (27)Al saturation pulse with heteronuclear dipolar recoupling yields dipolar dephasing of the (13)C signal, which only depends on the Al-C distance and the efficiency of the saturation pulse. Therefore, reliable distances can be obtained by rapid fitting of experimental data to an analytical expression. It is demonstrated that with natural isotopic abundance this approach allows recovery of Al-C distances of 216 pm for the covalent bond in lithium tetraalkyl aluminates, commonly used as a co-catalyst in olefin polymerization processes, and which range from 274 to 381 pm for the three carbon atoms in aluminum lactate. The accuracy of the measured internuclear distances is carefully estimated.

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Section: Methodsmentioning

confidence: 99%

Measurement of Aluminum–Carbon Distances Using S‐RESPDOR NMR Experiments

et al. 2012

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“…Recently, Gauvin et al [14] reported that silica-supported lanthanide silylamides are active for the homo-coupling of benzaldehyde to benzyl benzoate. But these supported catalysts were less active than their tris-amido precursors under the similar reaction conditions.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, characterization of amine-bridged bis(phenolate) yttrium alkyl complex and its catalytic behavior for the Tishchenko reaction

et al. 2008

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“…Following ac oordination-insertion mechanism,s urface-grafted lanthanide complexes are known to behavea sa ctive catalysts in many polymerization reactions. [47,50,51,57,58,[64][65][66][67] The first step of the mechanism involves the coordination of the monomer to the metal centre, the highert he Lewis acidic character of the metal,t he higher the activation of the monomer in the polymerization reaction.…”

Section: Probing the Lewis Acidity Of Graftedcomplexes:o =Pph 3 Coordmentioning

confidence: 99%

“…[43][44][45] Combined experimental and theoretical studies on the grafting of lanthanide com-plexes on silica have been recently reported. [46][47][48][49] They show that the formation of ac ovalent SiOÀLn bond requires the presence of hydroxyl groups on the surface, [46] the graftingr eaction of [Ln(N(SiMe 3 ) 2 ) 3 ]( Ln = La Nd, Sm) occurringt hrough a protonolysiso ft he LnÀNb ondb yt he surface silanols. As some of us have previously described, the graftingo famolecular complex on silica surfaces provides as ignificant modification of its catalytic properties.…”

Section: Introductionmentioning

confidence: 99%

“…and H−H inert bonds and to catalyse many polymerization reactions . Combined experimental and theoretical studies on the grafting of lanthanide complexes on silica have been recently reported . They show that the formation of a covalent SiO−Ln bond requires the presence of hydroxyl groups on the surface, the grafting reaction of [Ln(N(SiMe 3 ) 2 ) 3 ] (Ln=La Nd, Sm) occurring through a protonolysis of the Ln−N bond by the surface silanols.…”

Section: Introductionmentioning

confidence: 99%

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Grafting of Lanthanum Complexes on a Functionalized Graphene Surface: Theoretical Investigation on Ethylene and 1,3‐Butadiene Homo‐ and Co‐Polymerization

Bathellier

Moreno

Maron

et al. 2020

Chemistry A European J

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In this contribution, we describe the use of graphene as an efficient catalyst support and the role it plays in increasing the Lewis acidity of the supportedm etal complexes.B yadensity functional theorys tudy,w eshowt hat the [La(N(SiMe 3) 2) 3 ]c omplex can be easily grafted on graphene-OHa nd-COOHf unctionalized surfaces. Twos table mono-grafted compounds, (gO)-[La(N(SiMe 3) 2) 2 ]a nd (gOO)-[La(N(SiMe 3) 2) 2 ], are formed, behaving as stronger Lewis acids than the previously reported silica grafted analogues. To study the role of the graphene support in catalysis, we also computed the catalytic activity of the alkylated (gO)-[La(CH 3) 2 ]a nd (gOO)-[La(CH 3) 2 ]c omplexes in the ethylene and 1,3-butadiene homo-and co-polymerizationr eactions. Both compounds are efficient catalysts fort he homo-polymerization of the ethylene and 1,3-butadiene. For the 1,3butadiene homo-polymerization, the stereoselectivity outcome of the reactiond iffers according to the grafting site. The resultsc omputed for the co-polymerization reaction, finally,s how that the high stability of the allylic products leads to the formationo fb lock copolymers.

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Grafted lanthanide amides: Versatile catalysts for various transformations

Cited by 37 publications

References 53 publications

Measurement of Aluminum–Carbon Distances Using S‐RESPDOR NMR Experiments

Measurement of Aluminum–Carbon Distances Using S‐RESPDOR NMR Experiments

Synthesis, characterization of amine-bridged bis(phenolate) yttrium alkyl complex and its catalytic behavior for the Tishchenko reaction

Grafting of Lanthanum Complexes on a Functionalized Graphene Surface: Theoretical Investigation on Ethylene and 1,3‐Butadiene Homo‐ and Co‐Polymerization

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