Type
Text
Type
Dissertation
Advisor
Grubbs, Robert | Samspon, Nicole S | Ojima, Iwao | Montclare, Jin Kim.
Date
2015-08-01
Keywords
Chemistry | alternating copolymers, AROMP, bicyclic monomers, cyclobutene, cyclohexene, isomerization
Department
Department of Chemistry.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/77157
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Linear alternating copolymers have potential use as tools in the biochemical and material sciences. Cyclobutene-1-carboxylate esters and cyclohexene participate in an alternating ring-opening metathesis polymerization (AROMP) [Song, A.; Parker, K. A.; Sampson, N. S. J. Am. Chem. Soc. 2009, 131, 3444]. However, the molecular weight homogeneity of the copolymers resulting from the 1-cyclobutene ester/cyclohexene pair is limited by " cross metathesis" reactions that lead to undesired polymer dispersities and cyclic polymers. Therefore, strategies to inhibit intramolecular cross metathesis and to obtain linear alternating copolymers were undertaken. We set out to improve the AROMP process by screening reaction conditions to inhibit intramolecular cross metathesis. These conditions included co-solvents, additives, different catalysts and variation of monomers. Altering monomer steric contraints proved the most effective. Incorporation of bulky side chains provided linear alternating copolymers of limited lengths. These alternating copolymers support efficient energy transfer between side chains [Romulus, J.*; Tan, L.*; Weck, M.; Sampson, N. S. ACS Macro. Lett. 2013, 2, 749]. Linear alternating copolymers are synthetically accessible via AROMP with bicylic carbomethoxy olefin monomers and cyclohexene. Importantly, monomer methyl bicyclo[4.2.0]oct-7-ene-7-carboxylate in which the cyclobutene ring is fused to a cyclohexane provides rigorously linear (as opposed to cyclic), alternating copolymers free of cross metathesis. This pair was used to prepare alternating copolymers substituted with bromide and aldehyde moieties. These orthogonal functionalities provide an efficient route for post-polymerization modification with functional groups that are not compatible with AROMP. To demonstrate the utility of this approach, a tryptophan and dansyl fluorophore pair was conjugated onto the bromide/aldehyde derivatized polymers. FRET was observed between fluorophores confirming the substitutions, and illustrating the use of the polymer backbone for functional group presentation. Further investigation of the [4.2.0] monomers yielded bicyclo[4.2.0]oct-7-ene-7-carboxamides of primary amines. Theses amides were found to be susceptible to isomerization in the presence of (H2IMes)(PCy3)(Cl)2Ru=CHPh and yielded tetra-substituted bicyclo[4.2.0]oct-1(8)-ene-8-carboxamides. The isomerized amides underwent ring-opening metathesis in situ, and upon addition of cyclohexene, alternating copolymers were obtained. The tetrasubstituted amide monomers polymerize more rapidly than methyl bicyclo[4.2.0]oct-7-ene-7-carboxylate, enabling the construction of linear and extremely long alternating polymers. These synthetic methods provide an entry to applications requiring controlled polymer architectures. | 169 pages
Recommended Citation
Tan, Li, "Anti-Backbiting in Alternating Ring-Opening Metathesis Polymerization and Applications of Alternating Copolymers" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2993.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2993