dc.contributor.author | Jeong, Hyangsoo | |
dc.contributor.author | John, Jeremy M | |
dc.contributor.author | Schrock, Richard Royce | |
dc.date.accessioned | 2016-11-03T18:28:58Z | |
dc.date.available | 2016-11-03T18:28:58Z | |
dc.date.issued | 2015-10 | |
dc.identifier.issn | 0276-7333 | |
dc.identifier.issn | 1520-6041 | |
dc.identifier.uri | http://hdl.handle.net/1721.1/105182 | |
dc.description.abstract | Ring-opening metathesis polymerization (ROMP) is used to prepare trans-poly(A-alt-B) polymers from a 1:1 mixture of A and B where A is a cyclic olefin such as cyclooctene (A[subscript 1]) or cycloheptene (A[subscript 2]) and B is a large norbornadiene or norbornene derivative such as 2,3-dicarbomethoxy-7-isopropylidenenorbornadiene (B[subscript 1]) or dimethylspirobicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate-7,1'cyclopropane (B[subscript 2]). The most successful initiators that were
examined are of the type Mo(NR)(CHCMe[subscript 2]Ph)[OCMe(CF[subscript 3])[subscript 2]][subscript 2] (R = 2,6-Me[subscript 2]C[subscript 6]H[subscript 3] (1) or 2,6-iPr[subscript 2]C[subscript 6]H[subscript 3] (2)). The trans configuration of the AB linkages is proposed to result from the steric demand of B. Both anti-MB and syn-MB alkylidenes are observed during the copolymerization, where B was last inserted into a Mo=C bond, although anti-MB dominates as the reaction
proceeds. Anti-MB is lower in energy than syn-MB, does not react readily with either A or B, and interconverts slowly with syn-MB through rotation about the Mo=C bond. Syn-MB does not readily react with B, but it does react slowly with A (rate constant ~1 M[superscript -1] s
[superscript -1]) to give anti-MA and one trans-AB linkage. Anti-MA then reacts with B (rate constant ~300 M[superscript -1] s[superscript -1] or larger) to give syn-MB and the second trans-AB linkage. The reaction has been modeled using experimental data in order to obtain the estimated rate constants above. The reaction between anti-MA and A is proposed to give rise to AA linkages, but AA dyads can amount to <5%. Several other possible A and B monomers, initiators, and conditions were explored. | en_US |
dc.description.sponsorship | United States. Dept. of Energy (Grant DE-FG02-86ER13564) | en_US |
dc.language.iso | en_US | |
dc.publisher | American Chemical Society (ACS) | en_US |
dc.relation.isversionof | http://pubs.acs.org/doi/full/10.1021/acs.organomet.5b00709 | 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 | en_US |
dc.title | Formation of Alternating trans-A-alt-B Copolymers through Ring-Opening Metathesis Polymerization Initiated by Molybdenum Imido Alkylidene Complexes | en_US |
dc.type | Article | en_US |
dc.identifier.citation | Jeong, Hyangsoo, Jeremy M. John, and Richard R. Schrock. “Formation of Alternating trans-A-alt-B Copolymers through Ring-Opening Metathesis Polymerization Initiated by Molybdenum Imido Alkylidene Complexes.” Organometallics 34.20 (2015): 5136–5145. | 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 | Jeong, Hyangsoo | |
dc.contributor.mitauthor | John, Jeremy M | |
dc.contributor.mitauthor | Schrock, Richard Royce | |
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 | Jeong, Hyangsoo; John, Jeremy M.; Schrock, Richard R. | en_US |
dspace.embargo.terms | N | en_US |
dc.identifier.orcid | https://orcid.org/0000-0002-1788-4100 | |
dc.identifier.orcid | https://orcid.org/0000-0002-7405-6811 | |
dc.identifier.orcid | https://orcid.org/0000-0001-5827-3552 | |
mit.license | PUBLISHER_POLICY | en_US |