New Insights into the Polymerization of Methyl Methacrylate Initiated by Rare-Earth Borohydride Complexes: A Combined Experimental and Computational Approach
| dc.rights.license | open | |
| hal.structure.identifier | Laboratoire de physique et chimie des nano-objets [LPCNO] | |
| dc.contributor.author | BARROS, Noémi | |
| hal.structure.identifier | Laboratoire de Chimie des polymères organiques [LCPO] | |
| dc.contributor.author | SCHAPPACHER, Michèle | |
| hal.structure.identifier | Laboratoire de Chimie des polymères organiques [LCPO] | |
| dc.contributor.author | DESSUGE, Paul | |
| hal.structure.identifier | Laboratoire de physique et chimie des nano-objets [LPCNO] | |
| dc.contributor.author | MARON, Laurent | |
| hal.structure.identifier | Laboratoire de Chimie des polymères organiques [LCPO] | |
| hal.structure.identifier | Institut des Sciences Chimiques de Rennes [ISCR] | |
| hal.structure.identifier | Team 1 LCPO : Polymerization Catalyses & Engineering | |
| dc.contributor.author | GUILLAUME, Sophie M. | |
| dc.date.accessioned | 2020 | |
| dc.date.available | 2020 | |
| dc.date.created | 2007 | |
| dc.date.issued | 2008 | |
| dc.identifier.issn | 0947-6539 | |
| dc.identifier.uri | https://oskar-bordeaux.fr/handle/20.500.12278/20784 | |
| dc.description.abstractEn | Polymerization of methyl methacrylate (MMA) initiated by the rare-earth borohydride complexes [Ln(BH4)3(thf)3] (Ln=Nd, Sm) or [Sm(BH4)(Cp*)2(thf)] (Cp*=-C5Me5) proceeds at ambient temperature to give rather syndiotactic poly(methyl methacrylate) (PMMA) with molar masses n higher than expected and quite broad molar mass distributions, which is consistent with a poor initiation efficiency. The polymerization of MMA was investigated by performing density functional theory (DFT) calculations on an -C5H5 model metallocene and showed that in the reaction of [Eu(BH4)(Cp)2] with MMA the borate [Eu(Cp)2{(OBH3)(OMe)CC(Me)2}] (e-2) complex, which forms via the enolate [Eu(Cp)2{O(OMe)CC(Me)2}] (e), is calculated to be exergonic and is the most likely of all of the possible products. This product is favored because the reaction that leads to the formation of carboxylate [Eu(Cp)2{OOCC(Me)(CH2)}] (f) is thermodynamically favorable, but kinetically disfavored, and both of the potential products from a Markovnikov [Eu(Cp)2{O(OMe)CCH(Me)(CH2BH3)}] (g) or anti-Markovnikov [Eu(Cp)2{O(OMe)CC(Me2)(BH3)}] (h) hydroboration reaction are also kinetically inaccessible. Similar computational results were obtained for the reaction of [Eu(BH4)3] and MMA with all of the products showing extra stabilization. The DFT calculations performed by using [Eu(Cp)2(H)] to model the mechanism previously reported for the polymerization of MMA initiated by [Sm(Cp*)2(H)]2 confirmed the favorable exergonic formation of the intermediate [Eu(Cp)2{O(OMe)CC(Me)2}] (e) as the kinetic product, this enolate species ultimately leads to the formation of PMMA as experimentally observed. Replacing H by BH4 thus prevents the 1,4-addition of the [Eu(BH4)(Cp)2] borohydride ligand to the first incoming MMA molecule and instead favors the formation of the borate complex e-2. This intermediate is the somewhat active species in the polymerization of MMA initiated by the borohydride precursors [Ln(BH4)3(thf)3] or [Sm(BH4)(Cp*)2(thf)]. | |
| dc.language.iso | en | |
| dc.publisher | Wiley-VCH Verlag | |
| dc.subject.en | boron • density functional calculations • lanthanides • methyl methacrylate • p | |
| dc.title.en | New Insights into the Polymerization of Methyl Methacrylate Initiated by Rare-Earth Borohydride Complexes: A Combined Experimental and Computational Approach | |
| dc.type | Article de revue | |
| dc.identifier.doi | 10.1002/chem.200701438 | |
| dc.subject.hal | Chimie/Polymères | |
| bordeaux.journal | Chemistry - A European Journal | |
| bordeaux.page | 1881-1890 | |
| bordeaux.volume | 14 | |
| bordeaux.hal.laboratories | Laboratoire de Chimie des Polymères Organiques (LCPO) - UMR 5629 | * |
| bordeaux.issue | 6 | |
| bordeaux.institution | Bordeaux INP | |
| bordeaux.institution | Université de Bordeaux | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-00340293 | |
| hal.version | 1 | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-00340293v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Chemistry%20-%20A%20European%20Journal&rft.date=2008&rft.volume=14&rft.issue=6&rft.spage=1881-1890&rft.epage=1881-1890&rft.eissn=0947-6539&rft.issn=0947-6539&rft.au=BARROS,%20No%C3%A9mi&SCHAPPACHER,%20Mich%C3%A8le&DESSUGE,%20Paul&MARON,%20Laurent&GUILLAUME,%20Sophie%20M.&rft.genre=article |
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