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High-speed living polymerization of polar vinyl monomers by self-healing silylium catalysts

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High-speed living polymerization of polar vinyl monomers by self-healing silylium catalysts

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dc.contributor.author Zhang, Yuetao es_ES
dc.contributor.author Lay, Frank es_ES
dc.contributor.author García García, Pilar es_ES
dc.contributor.author List, Benjamin es_ES
dc.contributor.author Chen, Eugene Y. -X. es_ES
dc.date.accessioned 2016-09-20T09:04:21Z
dc.date.available 2016-09-20T09:04:21Z
dc.date.issued 2010
dc.identifier.issn 0947-6539
dc.identifier.uri http://hdl.handle.net/10251/70140
dc.description.abstract [EN] This contribution describes the development and demonstration of the ambient-temperature, high-speed living polymerization of polar vinyl monomers (M) with a low silylium catalyst loading (<= 0.05 mol (X) relative to M). The catalyst is generated in situ by protonation of a trialkylsilyl ketene acetal ((R)SKA) initiator (1) with a strong Bronsted acid. The living character of the polymerization system has been demonstrated by several key lines of evidence, including the observed linear growth of the chain length as a function of monomer conversion at a given [M]/[I] ratio, near-precise polymer number-average molecular weight (Me, controlled by the [M]/[I] ratio) with narrow molecular weight distributions (MWD), absence of an induction period and chain-termination reactions (as revealed by kinetics), readily achievable chain extension, and the successful synthesis of well-defined block copolymers. Fundamental steps of activation, initiation, propagation, and catalyst "self-repair" involved in this living polymerization system have been elucidated, chiefly featuring a propagation "catalysis" cycle consisting of a rate-limiting C-C bond formation step and fast release of the silylium catalyst to the incoming monomer. Effects of acid activator, catalyst and monomer structure, and reaction temperature on polymerization characteristics have also been examined. Among the three strong acids incorporating a weakly coordinating borate or a chiral disulfonimide anion, the oxonium acid [H-(Et(2)O)(2)](+)[B(C(6)F(5))(4)](-) is the most effective activator, which spontaneously delivers the most active R(3)Si(+), reaching a high catalyst turn-over frequency (TOF) of 6.0 x 10(3) h(-1) for methyl methacrylate polymerization by Me(3)Si(+) or an exceptionally high TOF of 2.4 x 10(5) h(-1) for n-butyl acrylate polymerization by iBu(3)Si(+), in addition to its high (>90%) to quantitative efficiencies and a high degree of control over M and MWD (1.07-1.12). An intriguing catalyst "self-repair" feature has also been demonstrated for the current living polymerization system es_ES
dc.description.sponsorship The work carried out at CSU was supported by the National Science Foundation (NSF-0848845). We thank Boulder Scientific Co. for the research gifts of B(C6F5)3, [Ph3C]+[B(C6F5)4] , and [HN(Me2)Ph]+[B- (C6F5)4]
dc.language Inglés es_ES
dc.publisher Wiley es_ES
dc.relation.ispartof Chemistry - A European Journal es_ES
dc.rights Reserva de todos los derechos es_ES
dc.subject Anions es_ES
dc.subject Brønsted acids es_ES
dc.subject Polar vinyl monomers es_ES
dc.subject Polymerization es_ES
dc.subject Silicon es_ES
dc.title High-speed living polymerization of polar vinyl monomers by self-healing silylium catalysts es_ES
dc.type Artículo es_ES
dc.identifier.doi 10.1002/chem.201000961
dc.relation.projectID info:eu-repo/grantAgreement/NSF//0848845/US/Living and Stereoselective Anionic Polymerization by Dinuclear Ambiphilic Silicon Propagators/ es_ES
dc.rights.accessRights Cerrado es_ES
dc.contributor.affiliation Universitat Politècnica de València. Instituto Universitario Mixto de Tecnología Química - Institut Universitari Mixt de Tecnologia Química es_ES
dc.description.bibliographicCitation Zhang, Y.; Lay, F.; García García, P.; List, B.; Chen, EY-. (2010). High-speed living polymerization of polar vinyl monomers by self-healing silylium catalysts. Chemistry - A European Journal. 16(34):10462-10473. doi:10.1002/chem.201000961 es_ES
dc.description.accrualMethod S es_ES
dc.relation.publisherversion http://dx.doi.org/ 10.1002/chem.201000961 es_ES
dc.description.upvformatpinicio 10462 es_ES
dc.description.upvformatpfin 10473 es_ES
dc.type.version info:eu-repo/semantics/publishedVersion es_ES
dc.description.volume 16 es_ES
dc.description.issue 34 es_ES
dc.relation.senia 241240 es_ES
dc.identifier.pmid 20665581
dc.contributor.funder National Science Foundation, EEUU


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