dc.contributor.author | Forrest, William P. | |
dc.contributor.author | Axtell, Jonathan Clayton | |
dc.contributor.author | Schrock, Richard Royce | |
dc.date.accessioned | 2015-04-30T15:15:37Z | |
dc.date.available | 2015-04-30T15:15:37Z | |
dc.date.issued | 2014-04 | |
dc.date.submitted | 2014-03 | |
dc.identifier.issn | 0276-7333 | |
dc.identifier.issn | 1520-6041 | |
dc.identifier.uri | http://hdl.handle.net/1721.1/96860 | |
dc.description.abstract | We have employed 2,3-dicarbomethoxynorbornadiene (DCMNBD) as a monomer to explore new tungsten oxo alkylidene complexes as initiators for stereoregular ROMP (ring-opening metathesis polymerization). The initiators include MAP (monoaryloxide pyrrolide) oxo alkylidene complexes with the general formula W(O)(CHCMe[subscript 2]Ph)(Me[subscript 2]Pyr)(OAr) (Me[subscript 2]Pyr = 2,5-dimethylpyrrolide, OAr = an aryloxide) and W(O)(CHCMe[subscript 2]Ph)(OR)[subscript 2] (OR = an aryloxide or OC(CF[subscript 3])[subscript 3]), or PPh[subscript 2]Me or CH[subscript 3]CN adducts thereof. We have found that MAP initiators yield cis,syndiotactic-poly(DCMNBD) as a consequence of stereogenic metal control. In contrast, W(O)(CHCMe[subscript 2]Ph)(OR)[subscript 2](L) initiators (where L = PPh[subscript 2]Me or acetonitrile) are strongly biased toward formation of cis,isotactic structures, while W(O)(CHCMe[subscript 2]Ph)(OR)[subscript 2] initiators are strongly biased toward formation of cis,syndiotactic structures. Addition of B(C[subscript 6]F[subscript 5])[subscript 3] to W(O)(CHCMe[subscript 2]Ph)(Me[subscript 2]Pyr)(OR) species leads to a dramatic increase in the rate of polymerization and to an increase in the cis,syndiotacticity of the polymer (if not already high), while addition of B(C[subscript 6]F[subscript 5])[subscript 3] to W(O)(CHCMe[subscript 2]Ph)(OR)[subscript 2] initiators leads to a dramatic increase in the rate of polymerization and to the formation of highly cis,syndiotactic polymers. All evidence supports the proposal that 16e W(O)(CHCMe[subscript 2]Ph)(OR)[subscript 2](L) complexes can operate either through loss of L to yield 14e W(O)(CHCMe[subscript 2]Ph)(OR)[subscript 2] species (which yield largely cis,syndiotactic-poly(DCMNBD)) or by directly reacting with DCMNBD to yield an 18e intermediate and largely cis,isotactic-poly(DCMNBD). All polymerizations by W(O)(CHCMe[subscript 2]Ph)(OR)[subscript 2](L) and W(O)(CHCMe[subscript 2]Ph)(OR)[subscript 2] initiators are proposed to operate through some version of chain end control. | en_US |
dc.description.sponsorship | United States. Dept. of Energy (DE-FG02-86ER13564) | en_US |
dc.description.sponsorship | National Science Foundation (U.S.) (CHE-1111133) | en_US |
dc.language.iso | en_US | |
dc.publisher | American Chemical Society (ACS) | en_US |
dc.relation.isversionof | http://dx.doi.org/10.1021/om5002364 | en_US |
dc.rights | Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. | en_US |
dc.source | Prof. Schrock via Erja Kajosalo | en_US |
dc.title | Tungsten Oxo Alkylidene Complexes as Initiators for the Stereoregular Polymerization of 2,3-Dicarbomethoxynorbornadiene | en_US |
dc.type | Article | en_US |
dc.identifier.citation | Forrest, William P., Jonathan C. Axtell, and Richard R. Schrock. “Tungsten Oxo Alkylidene Complexes as Initiators for the Stereoregular Polymerization of 2,3-Dicarbomethoxynorbornadiene.” Organometallics 33, no. 9 (May 12, 2014): 2313–2325. | en_US |
dc.contributor.department | Massachusetts Institute of Technology. Department of Chemistry | en_US |
dc.contributor.approver | Schrock, Richard Royce | en_US |
dc.contributor.mitauthor | Forrest, William P. | en_US |
dc.contributor.mitauthor | Axtell, Jonathan Clayton | en_US |
dc.contributor.mitauthor | Schrock, Richard Royce | en_US |
dc.relation.journal | Organometallics | en_US |
dc.eprint.version | Author's final manuscript | en_US |
dc.type.uri | http://purl.org/eprint/type/JournalArticle | en_US |
eprint.status | http://purl.org/eprint/status/PeerReviewed | en_US |
dspace.orderedauthors | Forrest, William P.; Axtell, Jonathan C.; Schrock, Richard R. | en_US |
dc.identifier.orcid | https://orcid.org/0000-0001-5827-3552 | |
mit.license | PUBLISHER_POLICY | en_US |
mit.metadata.status | Complete | |