Mechanistic insights towards new reactions and materials
Abstract/Contents
- Abstract
- Catalysis is the enabling science of polymer synthesis, and new catalytic mechanisms yield new materials. The developement of organocatalysts for polymer synthesis has, particularly in the last decade, spawned an impressive array of new catalysts, processes and mechanistic insights. While the focus of most recent research in organocatalysis has concentrated on enantioselective synthesis of small molecules, organocatalysis offers a number of opportunities in polymer synthesis and was among the earliest methods of catalyzing the synthesis of polyesters. The enthalpy of ring opening of cyclic esters or carbonates drives the majority of organocatalyic polymerization reactions catalyzed by a still-evolving array of organocatalysts. Organocatalysts are thought to effect polymerization of cyclic esters by several mechanisms. Some proceed via a monomer activated mechanism whereby the catalyst activates the cyclic ester towards transesterification to the polymer chain. Others operate by an alcohol activation mechanism where the alcoholic end group of the growing polymer chain is activated to induce transesterification. Some are thought to be operative by a combination of these mechanisms. The unique reactivity offered by organocatalysts has provided access to precisely controlled macromolecular architectures and well-defined (co)polymers including a wide array of functionality. The notion that rate must be sacrificed to implement organocatalysts is fading with the discovery of transesterification organocatalysts that rival in reaction rate even the most active metal-containing catalysts. Cyclopentadienyl ruthenium complexes with quinaldic acid-type ligands are robust allylation catalysts in alcoholic solvents, but they are sensitive to dissolved oxygen, requiring reactions to be conducted in an inert atmosphere. Moving from alcoholic to neat aqueous solvents decreases the rate of deallylation but allows the reaction to be conducted in air without loss of catalyst activity over the course of the reaction. These complexes are also effective for the formation of allyl ethers, allowing the synthesis of poly(2,5-dihydrofuran) from the condensation polymerization of 2-cis-butene-1,4-diol. This material was previously deemed inaccessible via traditional polycondensation catalysts.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Copyright date | 2011 |
| Publication date | 2010, c2011; 2010 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Kiesewetter, Matthew Karl |
|---|---|
| Associated with | Stanford University, Department of Chemistry |
| Primary advisor | Waymouth, Robert M |
| Thesis advisor | Waymouth, Robert M |
| Thesis advisor | Kool, Eric T |
| Thesis advisor | Trost, Barry M |
| Advisor | Kool, Eric T |
| Advisor | Trost, Barry M |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Matthew Karl Kiesewetter. |
|---|---|
| Note | Submitted to the Department of Chemistry. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2011. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2011 by Matthew Karl Kiesewetter
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...