STRUCTURE-FUNCTION RELATIONSHIPS OF FUNCTIONALIZED PENTACARBOXYCYCLOPENTADIENES IN CATIONIC POLYMERIZATION OF VINYL ETHERS
Access to this document is restricted. Some items have been embargoed at the request of the author, but will be made publicly available after the "No Access Until" date.
During the embargo period, you may request access to the item by clicking the link to the restricted file(s) and completing the request form. If we have contact information for a Cornell author, we will contact the author and request permission to provide access. If we do not have contact information for a Cornell author, or the author denies or does not respond to our inquiry, we will not be able to provide access. For more information, review our policies for restricted content.
Isotactic, high molecular weight poly(vinyl ether)s (PVEs) have gained interest due to their combination of mechanical performance and adhesive properties. However, PVEs remain largely untouched by industry due to the cost, limitations, and synthetic complexity of the few stereoselective catalysts that can make them. The Brønsted acid catalyst 1,2,3,4,5--pentacarbomethoxycyclopentadiene (PCCP-0) has been shown to instigate cationic polymerizations in the past, but lacks stereoselectivity and polymerizes vinyl ethers to low molecular weights without the assistance of a hydrogen bond donor. In this work, we aim to solve these problems by functionalizing PCCP-0. Herein, various new electronically and sterically diverse catalysts were made, both chiral and achiral, by functionalizing PCCP-0 with various divergent groups. Subsequently, cationic polymerizations of vinyl ethers using these catalysts were performed. GPC and NMR measurements of molecular weights and tacticities were taken, and the results rationalized via electronic considerations and density functional theory structures. We found that a PCCP catalyst functionalized with bis(trifluoromethyl)phenyl derivatives was able to polymerize IBVE to high molecular weights (> 100 kDa). The synthesis of a new set of organic catalysts detailed in this work and elucidation of their structure-property relationships, draws us closer to the adoption of isotactic poly(vinyl ether)s on an industrial scale.