Highly reactive yttrium alkoxide as new initiator for the polymerization of β‐butyrolactone

Borgne, Alain Le; Pluta, Christian; Spassky, Nicolas

doi:10.1002/marc.1994.030151208

Cited by 77 publications

(50 citation statements)

References 8 publications

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“…[19,20] Ring-opening polymerization of racemic b-butyrolactone: Surprisingly, although not stereoselective for the polymerization of rac-lactide, complexes 1-4 proved able to control the stereoselective ROP of b-butyrolactone (BBL) to produce syndiotactic rich poly(hydroxy-3-butyrate) (PHB) (Scheme 5). Previous studies have shown that the ROP of BBL is generally much more difficult than that of lactide, [21] and very few metal-based initiators have been shown to induce high stereoselectivities.…”

Section: A C H T U N G T R E N N U N G (10 3 )mentioning

confidence: 99%

Bis(guanidinate) Alkoxide Complexes of Lanthanides: Synthesis, Structures and Use in Immortal and Stereoselective Ring‐Opening Polymerization of Cyclic Esters

Ajellal

Lyubov

Sinenkov

et al. 2008

Chemistry A European J

161

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A series of new bis(guanidinate) alkoxide Group 3 metal complexes [Ln((Me3Si)2NC(NiPr)2)2(OR)] (R=OtBu, Ln=Y, Nd, Sm, Lu; R=OiPr, Ln=Y, Nd, Lu) has been synthesized. X-ray structural determinations revealed that bis(guanidinate) tert-butoxides are monomeric complexes. The isopropoxide complex [Y((Me3Si)2NC(NiPr)2)2(OiPr)] undergoes slow decomposition in solution, to afford the unusual dimeric amido complex [(Y((Me3Si)2NC(NiPr)2)2(mu-N(iPr)C triple chemical bond N))2]. Complexes [Ln((Me3Si)2NC(NiPr)2)2(OR)] (R=OtBu, Ln=Y, Nd, Sm, Lu; R=OiPr, Ln=Y, Nd, Lu) are active catalysts/initiators for the ROP of rac-lactide and rac-beta-butyrolactone under mild conditions. Most of those polymerizations proceed with a significant degree of control. Bis(guanidinate) alkoxides appear to be well suited for achieving immortal polymerization of lactide, through the introduction of large amounts of isopropanol as a chain-transfer agent. The synthesized complexes are able to promote the stereoselective ROP of rac-beta-butyrolactone to afford syndiotactic poly(hydrobutyrate) through a chain-end control mechanism, while they are surprisingly non-stereoselective for the ROP of lactide under strictly similar conditions.

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Section: A C H T U N G T R E N N U N G (10 3 )mentioning

confidence: 99%

Bis(guanidinate) Alkoxide Complexes of Lanthanides: Synthesis, Structures and Use in Immortal and Stereoselective Ring‐Opening Polymerization of Cyclic Esters

Ajellal

Lyubov

Sinenkov

et al. 2008

Chemistry A European J

161

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“…[12,18] Yttrium and Samarium derivatives are less reactive as seen in the example of l-oxo alkoxides of the Ln 5 (l-O)(OiPr) 13 type. [18] On the other hand yttrium tris(isopropoxyethoxide) Y(OCH 2 CH 2 OiPr) 3 is more reactive than the corresponding (l-oxo) cluster Y 5 (l-O)(OiPr) 13 . [19] The number of polymer chains started by one catalyst molecule was found to be 3 for Y(OCH 2 CH 2 OiPr) 3 , i. e., one polymer chain per alkoxide group [19] and 2.6 (13/5) for yttrium and lanthanum clusters.…”

Section: Measurementsmentioning

confidence: 99%

“…[5,[7][8][9][10] Recently was reported that rare earth alkoxides display a very high reactivity in the polymerization of lactones and lactides. [11][12][13][14][15][16][17] (D,L) and (L)-lactides have been polymerized using lanthanide oxoalkoxide clusters of Ln 5 (l-O)(OiPr) 13 type [18] and Y(OC 2 H 4 OiPr) 3 [19] as initiator systems.…”

Section: Introductionmentioning

confidence: 99%

Inter- and intramolecular ester exchange reactions in the ring-opening polymerization of (D,L)-lactide using lanthanide alkoxide initiators

Spassky¹,

Simic

Montaudo³

et al. 2000

Macromol. Chem. Phys.

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Polylactide samples obtained by the ring‐opening polymerization of (D,L)‐lactide by using different lanthanide alkoxide initiators were examined by SEC, 13C NMR and MALDI‐TOF MS techniques. The evidence of substantial transesterification was observed in the case of a polymerization initiated by lanthanum alkoxide and bimetallic aluminium‐yttrium alkoxide initiators. In the case of Y and Sm alkoxide initiators, the MWD remains narrow up to high conversions for reasonable polymerization times, but the prolongation of the post‐polymerization time increases the amount of ester‐exchange reactions. The extent of the transesterification reactions was evaluated on the basis of the intensity of the stereosequence resonances for the methine carbon signal in the 13C NMR spectra. MALDI‐TOF MS analysis revealed the presence of odd‐membered oligomers in all spectra. Thus, transesterification reactions occur from the beginning of the polymerization. Linear and cyclic oligomers were detected in some cases indicating the simultaneous occurrence of inter‐ and intramolecular exchange reactions. The microstructure analysis of the polymers by 13C NMR spectroscopy indicates a preference for a syndiotactic addition during the polymerization process.

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“…Among them, aluminium or zinc derivatives such as aluminium isopropoxide 2,3) , l-oxo-bimetallic alkoxides 4) , porphyrins 5,6) and dialkylaluminium alkoxides 7,8) deserve to be mentioned. More recently, rare earth alkoxides have been described as quite interesting initiators for the polymerization of e-caprolactone 9,10) and lactides 11,12) . As an example, polymerization carried out with yttrium isopropoxide at room temperature is very fast, and a living character has been observed with low polydispersities.…”

Section: Introductionmentioning

confidence: 99%

Anionic coordinated polymerization ofɛ-caprolactone with aluminium, zirconium and some rare earths alkoxides as initiators in the presence of alcohols

Miola-Delaite

Hamaide²,

Spitz

1999

Macromol. Chem. Phys.

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SUMMARY: The kinetics of the polymerization of e-caprolactone initiated with various Lewis acid metal alkoxides (Al, Zr and rare earths such as Y, Sm, Nd) in the presence of excess alcohol has been investigated. Whatever the metal, the activity depends strongly on the [Alcohol]/[Metal] ratio and goes through a maximum, except for Zr, for which the increase of alcohol concentration leads to a continuous decrease of the reaction rate. The activities obtained for zirconium butoxide as initiator are lower than for aluminium isopropoxide at room temperature but the activation energy is higher. No transesterification reactions have been noticed during polymerization. The polymerization can be described according to a living process with fast transfer reaction, so that the molecular weight is easily controlled by the [Monomer]/[Alcohol] ratio. Rare earths alkoxides (Y, Sm, Nd) result in higher activities. Although some transesterification reactions are observed if leaving the polymer chains in contact with the active centers, functionalized oligomers can be obtained within less than 5 min with yttrium or samarium isopropoxide as initiators and benzyl alcohol in excess.

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Highly reactive yttrium alkoxide as new initiator for the polymerization of β‐butyrolactone

Cited by 77 publications

References 8 publications

Bis(guanidinate) Alkoxide Complexes of Lanthanides: Synthesis, Structures and Use in Immortal and Stereoselective Ring‐Opening Polymerization of Cyclic Esters

Bis(guanidinate) Alkoxide Complexes of Lanthanides: Synthesis, Structures and Use in Immortal and Stereoselective Ring‐Opening Polymerization of Cyclic Esters

Inter- and intramolecular ester exchange reactions in the ring-opening polymerization of (D,L)-lactide using lanthanide alkoxide initiators

Anionic coordinated polymerization ofɛ-caprolactone with aluminium, zirconium and some rare earths alkoxides as initiators in the presence of alcohols

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