Nitrogen-containing lanthanide complexes: initiators or real catalysts for the ε-caprolactone polymerisation?

Visseaux, Marc; Brachais, Claire‐Hélène; Boisson, Christophe; Tortosa, Karine

doi:10.1016/s1387-1609(00)00160-2

Cited by 5 publications

(5 citation statements)

References 14 publications

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“…Indeed, Visseaux and co-workers have provided evidence of Ln-O bonds being active in the polymerization process and proposed that Ln-N bonds are converted to such species by reaction with e-CL. 21 In that work, it was proposed that -N(SiMe 3 ) 2 extracts a proton in the a position of the carbonyl group of e-CL causing the alkoxide-Sm species to precipitate, with the Sm-O bond being active in the polymerization process.…”

Section: Introductionmentioning

confidence: 99%

Lanthanide chloride complexes of amine-bis(phenolate) ligands and their reactivity in the ring-opening polymerization of ε-caprolactone

et al. 2008

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Reaction of two equivalents of n-BuLi with sterically demanding amine-bis(phenol) compounds, H 2 O 2 NN R (Me 2 NCH 2 CH 2 N{CH 2 -3,5-R 2 -C 6 H 2 OH} 2 ; R = t-Bu or t-Pe (tert-pentyl)) yields isolable lithium complexes, Li 2 (O 2 NN R ), in good yields. Upon reaction with one equivalent of LnCl 3 (THF) x , the lithium salts afford rare earth amine-phenolate chloride complexes in good yields, Ln(O 2 NN R )Cl(THF); Ln = Y, Yb, Ho, Gd, Sm, Pr. Crystals of Y(O 2 NN t-Bu )Cl(THF), 1, and Sm(O 2 NN t-Bu )Cl(DME), 2, suitable for single crystal X-ray crystallographic analysis were obtained. In contrast to previously reported [{Gd(O 2 NN t-Pe )(THF)(l-Cl)} 2 ] and related La and Sm complexes, these species are monomeric. 1 contains Y in a distorted octahedral environment bonded to two amine, two phenolate, one THF and one chloride donor. 2 contains Sm in a distorted capped trigonal prismatic environment bonded to two amine, two phenolate, two DME oxygens and one chloride donor. The Ln(O 2 NN t-Pe )Cl(THF) complexes were active initators for the controlled ring-opening polymerization of e-caprolactone with a tendency to form low molecular weight cyclic polyesters (M n 3000-5000). The conversion rates, although slower than related amido and alkyl species, were different for monomeric and dimeric initiators. The size of the metal centre also affected the conversions and the molecular weights achieved.

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Section: Introductionmentioning

confidence: 99%

Lanthanide chloride complexes of amine-bis(phenolate) ligands and their reactivity in the ring-opening polymerization of ε-caprolactone

et al. 2008

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“…This can be due to the reduced accessibility of the samarium centres in the SmI initiator under these conditions. Such a behaviour has already been observed 37. Table 5 summarises some significant experimental results.…”

Section: Resultsmentioning

confidence: 99%

Diene/olefin/polar monomer copolymerisation: unprecedented functional polymers from a rare earth catalyst

Bonnet

Barbier‐Baudry

Dormond

et al. 2002

Polymer International

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“…A mechanistic study of the e-caprolactone polymerization involved with amido compounds will be given in a future paper. [17] Heterogeneous Medium…”

Section: Homogeneous Mediummentioning

confidence: 99%

Homogeneous and Heterogeneous Polymerization ofɛ-Caprolactone by Neodymium Alkoxides Prepared In Situ

Tortosa

Hamaide

Boisson³

et al. 2001

Macromol. Chem. Phys.

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Nitrogen-containing lanthanide complexes: initiators or real catalysts for the ε-caprolactone polymerisation?

Cited by 5 publications

References 14 publications

Lanthanide chloride complexes of amine-bis(phenolate) ligands and their reactivity in the ring-opening polymerization of ε-caprolactone

Lanthanide chloride complexes of amine-bis(phenolate) ligands and their reactivity in the ring-opening polymerization of ε-caprolactone

Diene/olefin/polar monomer copolymerisation: unprecedented functional polymers from a rare earth catalyst

Homogeneous and Heterogeneous Polymerization ofɛ-Caprolactone by Neodymium Alkoxides Prepared In Situ

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